Reproduced from Ross Cranston, Jan Ramberg & Jacob Ziegel, eds., Commercial Law Challenges in the 21st Century; Jan Hellner in memorium, Stockholm Centre for Commercial Law Juridiska institutionen (2007) 185-200 with the permission of the author and the Stockholm Centre

1. Introduction
2. The Problem
3. Solution inside the CISG
4. General Starting Point -- Last Shot
   1. Incorporation of Standard Terms
   2. Art. 19 CISG
         a)    Basic principles: complete correspondence between offer and acceptance
         b)    Exception for immaterial deviation from offer
         c)    Borderline between material and immaterial deviations
         d)    Discretion as to the qualification as material or immaterial
         e)    Overarching principle of party autonomy
   3. Last Shot
5. Exception - Knock Out
   1. Performance of the Contract
         a)    Full performance by both parties
         b)    Partial performance by both parties
         c)    Performance by one party
         d)    Range of the knock out
   2. Assent to the Contract in Other Forms than by Performance?
   3. Application of the Knock Out Rule also before the Performance Phase?
6. Final Remarks

I. INTRODUCTION

The Vienna Sales Convention (CISG) contains in its second part rules on the formation of contract. They are the almost perfect expression of the traditional view on how a contract is concluded, namely by subsequent declarations of two parties whose intentions as stated in their offer and acceptance must be essentially ad idem. The CISG model concerning the formation of contract has been more or less copied by the UNIDROIT Principles of International Commercial Contracts and by the Principles of European Contract Law, the so-called Lando Principles. But both sets of Principles have wisely added rules on conflicting standard terms [1] which the CISG had still omitted. More than a quarter of a century after the creation of the CISG one should think that firm solutions of the problem of the battle of forms have been developed and accepted also under the CISG. But there is still some uncertainty with respect to the correct solution as recent case material shows.[2]

The following text pursues the different approaches and tries to reconcile them. It is devoted to the memory of Jan Hellner who took a vivid interest in the Uniform Sales Law and whose articles on this subject enriched the international discussion. Already in 1986 he wrote on "The Vienna Convention and Standard Form Contracts".[3] It is worthwhile to explore whether his insights are still valid more than twenty years later.

II. THE PROBLEM

Nonetheless, even at the time of conclusion or intended conclusion of their contract the parties are generally very well aware of the fact that their respective standard forms do not conform in every respect but differ in some way -- normally at least with regard to the applicable law and the jurisdiction.[8] The parties, respectively their lawyers become interested in the standard terms and their precise differences only when a dispute arises.[9] Then, they take the standard terms seriously and try to use their own general conditions as a safety belt or as a threatening stick by which the other party should be impressed in order to reach a favourable compromise.

Is the consequence of the preceding observations that standard terms have to be regarded as second-class contract terms -- quite apart from their valid incorporation and material control where they are already treated as second or at best a separate class since long? But if so with which effect? At least in the eyes of the parties the standard terms have not the same weight as the first class terms which are indispensable for the existence of the contract.

However, the battle of forms problem is only a facet of the general question of how perfect the agreement of the parties must be in order to conclude a contract or, viewed from the other side, how much disagreement is acceptable and will not yet hinder the formation of a contract. [page 187]

III. SOLUTION INSIDE THE CISG

Turning on the CISG, the first question is whether the problem of the battle of forms is at all covered by the Convention. Today, the clearly prevailing view answers this question in the affirmative.[10] Although the CISG -- as mentioned in contrast to the UNIDROIT and Lando Principles -- contains no specific provision on conflicting standard terms it is argued that its general rules on formation of contract allow a solution. The sedes materiae is Art. 19 CISG combined with the general principle of party autonomy as enshrined in Art. 6 CISG. And indeed, it would be more than unfortunate if such an important standard problem as the battle of forms had to be dealt with outside the CISG in accordance with the applicable national law. The CISG provides a full set of rules on the formation of contract. Therefore, a solution must be sought within their ambit. However, less easy is the answer how the battle of forms should be decided.

IV. GENERAL STARTING POINT -- LAST SHOT

At the outset, it must be stated that general conditions do not matter at all unless they have become a valid part of the offer or acceptance. Unfortunately the Convention is also silent on the incorporation of standard terms. At present, this problem is as well disputed but the view prevails that absent any prior agreement, practice between the parties, international trade usage or good faith requirement standard terms must be made available to the other party, regularly by sending them, and the offer or acceptance must contain the clear notice that the general terms are part of it.[11] Moreover, [page 188] the standard forms must be exchanged during the formative phase of the contract. General contract terms which are later included for instance on invoices or the like do not become part of the contract.[12] Only if all these requirements are met (which cannot be further discussed here) the battle of forms problem can arise.

2. Art. 19 CISG

a) Basic principle: complete correspondence between offer and acceptance

Under the CISG Art. 19 is the battlefield on which the battle of forms must be fought til its bitter end. Therefore the heights and depths of this field have first to be explored. The Sales Convention follows the widespread rule that an acceptance must unequivocally and in principle without modification express consent to the offer (Art. 18 CISG -- mirror image principle). As a rule any deviation from the contents of the offer makes an acceptance a rejection and counter-offer (Art. 19 par. 1 CISG). This counter-offer requires itself acceptance which can and often will occur in that the other party merely starts performance (dispatch of the goods or payment of the price). But in the absence of any express or implied acceptance no contract is concluded. Mere silence or inactivity is not sufficient to bring a contract about (Art. 18 par. 1 sent. 2 CISG).

b) Exception for immaterial deviation from offer

For practical reasons the CISG allows one exception from the strict doctrine that an acceptance must fully correspond to the offer (the underlying idea of this doctrine being that the offeror shall not be forced to accept something he did neither intend nor consent to): If the deviation is not material the acceptance concludes the contract nonetheless to its terms unless the offeror objects to it without undue delay (Art. 19 par. 2 CISG). In this case of immaterial modifications it is acceptable that the offeror must communicate its dissent rather promptly.[13] Otherwise its consent is irrebuttably presumed. [page 189]

c) Boarderline between material and immaterial deviations

The core issue under Art. 19 then is to draw the boarderline between material and immaterial deviations from the original offer. Art. 19 par. 3 CISG tries to give some examplary advice but its non-exhaustive list declares in fact almost any kind of deviation as material: not only modifications of the essentials of the bargain (price, payment, quality and quantity of the goods, place and time of delivery) are material but also changes concerning the liability of the parties or the settlement of disputes. Settlement of disputes comprises for instance the case that a jurisdiction clause,[14] an arbitration clause [15] or even a choice of law clause [16] is introduced for the first time or is varied. Only few terms are imaginable which are not mentioned, for instance penalty clauses, clauses concerning securities or concerning rights of withdrawal.[17] In most cases they will qualify as material modifications.[18]

d) Discretion as to the qualification as material or immaterial

Though the wording of Art. 19 par. 3 CISG sounds as if its list qualifies any deviation concerning one of the mentioned terms definitely and finally as material it is the rather clearly prevailing view that the provision constitutes only a rule of interpretation.[19] It gives therefore a certain discretion to qualify deviations with regard to even the essentialia negotü as immaterial.[20] The general guideline whether a deviation is immaterial should be whether a reasonable person in the shoes of the offeror would regard it as so minor that with respect to the principles of good faith and fair dealing it would [page 190] accept it.[21] For instance, a deviation in favour of the offeror (e.g. transport of goods to the offeror without extra cost) are immaterial in the sense of Art. 19 par. 3 CISG.[22] The same is true if the deviation only repeats or specifies the existing law.[23]

e) Overarching principle of party autonomy

However, before all these refinements of Art. 19 CISG are applied the fundamental principle of party autonomy must be taken due account of. Because of this over arching principle of the Convention [24] the offeror and the acceptor can give their offer or acceptance a certain meaning that then takes precedence over the provisions of Art. 19 CISG. Therefore, it must always be first examined whether the offer allows explicitly or impliedly the acceptor to fix or specify any of the conditions of the offer. Secondly, it must be examined whether the acceptor has unequivocally accepted the offer and has only added one or more additional new proposals which the offeror is invited to separately accept or reject. Further, a specific meaning of the offer or acceptance can also follow from practices which the parties have already established between them or from international usages in the particular trade (Art. 9 CISG). Finally, the parties can have derogated from Art. 19 CISG at all.

3. Last Shot

A literal and strict application of the pre-mentioned principles of Art. 19 CISG to cases of conflicting standard terms would firstly mean that the divergences between the standard terms of the parties are regularly material in the sense of Art. 19 par. 3.[25] At least the routinely included choice of law clauses and jurisdiction/arbitration clauses would in all probability differ and constitute a material modification. But also further material terms -- for instance a retention of title clause of the seller -- are often included in the terms of only one party. Therefore material divergences between the [page 191] respective standard terms are the rule. That would secondly mean that as long as the parties continue to exchange their standard terms no contract is concluded even if one party starts performance (accompanied by sending the standard terms again). Under Art. 19 CISG a contract is only concluded if one party gives in and does something which expresses consent without no longer sending or otherwise relying on the own standard terms. Then the form fired last constitutes the basis of the contract; the last shot of forms decides the battle. Strictly applied this would be the solution under Art. 19 CISG.

The accidental results, shortcomings and generally unconvincing outcome of this theory have often been described and criticized.[26] The last shot theory is particularly unsatisfactory when the parties have started performance but still insist on their respective conflicting standard terms. Then under an inflexible application of Art. 19 CISG the conclusion of the contract fails despite the general and demonstrated agreement of the parties concerning the essentials of the contract.[27] But it is likewise unsatisfactory that a party shall have surrendered to the conditions of the other side when it starts acts of performance without again sending the own conditions. The inferral of such an intention of that party is regularly a mere guess. Hellner drew from all that already [in] 1986 the conclusion that "the battle of forms" should not be judged at all by the rules on offers and counter-offers."[28]

The dilemma of Art. 19 CISG can hardly be overcome within the four corners of this article alone. The way out is the retreat to the basic principle of party autonomy (Art. 6 CISG) and to what is probably a more realistic estimation of the parties' intentions (see thereto under V.). Nonetheless, Art. 19 par 1 CISG remains the basis. The parties are free and must remain free to reject an offer and answer with a counter-offer. However, they must do it in a clear and unequivocal way so that a reasonable person would understand it in this way. Insofar the standard of Art. 8 CISG has to be applied.[29] The [page 192] mere use of conflicting general terms is however no clear indication that an offer as such is rejected at the peril that no contract comes into existence. Standard terms are, as mentioned, provisions which are designed to care for situations when something goes wrong with the contract. They are therefore fundamentally based on the assumption, and found the presumption, that a valid contract has been concluded. Only in that event they are intended to have effects. In this sense they are second class contract terms which enter the battlefield only as a reserve army after the battle, namely the dispute between the parties has started. If a party wants that no contract be concluded unless the own standard terms are accepted -- which this party is perfectly free to achieve -- this intention must then be declared to the other party in another way than by general contract terms.

According to the preceding considerations the ambit of the last shot rule should be rather restricted in case of a battle of forms. Only if there is a clear indication of disagreement otherwise than by standard terms can there be a relevant dissent and no conclusion of a contract. Or, if there is an unambivalent surrender of one party to the standard conditions of the other -- which cannot be merely inferred from the fact that a party starts performance without insisting on the own conditions [30] -- then the contract is concluded to these conditions. In all other cases the solution must however be different.

V. EXCEPTION -- KNOCK OUT

The preferable solution for these other cases bears no less an aggressive name -- knock out rule -- though its character is rather solomonic. It accepts the agreement of the parties on the essentialia negotü, leaves the non-conflicting standard terms of both sides as part of the contract intact and substitutes the conflicting terms by the respective provisions of the Convention or the otherwise applicable law.[31] The literature on the CISG favours this [page 193] rule [32] although also the contrary view is strongly advocated.[33] The more recent court practice tends also towards the knock out rule [34] but contrary decisions can be found as well.[35]

It must also be noted that recent international developments clearly support the knock out rule. The UNIDROIT Principles of 1994/2004 provide that in case of an agreement except on all of the standard terms a contract is concluded; the contract then includes the common terms and excludes the conflicting ones. However, each party is free to indicate in advance or later by clear and due notice that it will not be bound by such a contract.[36] With almost identical contents equally the Principles of European Contract Law of 2000 have adopted the knock out rule.[37] Even more general is now § 2-207 of the influential American Uniform Commercial Code (UCC) as very recently amended (2005): If the parties have concluded a contract or recognise by their conduct its existence then the contents of the contract is formed of those terms which in the records of both parties appear or on which the parties agree. This provision restricts the knock out rule not only to conflicting standard terms though it certainly comprises them ("records"). This general development towards the knock out rule which was not in sight when the CISG was drafted in 1980 should also be taken into account when a reasonable solution under the CISG is to be developed.

The precise ambit of the knock out rule deserves, however, closer discussion. [page 194]

1. Performance of the Contract

a) Full performance by both parties

The knock out rule enjoys greatest support if both parties have already performed the contract.[38] Of particular interest in this respect is the leading decision of the German Federal Court (BGH) [39] which concerned a German-Dutch sale of milk-powder. Both parties had agreed to the contract on the basis of their standard contract terms which differed on the the regulation of liability for damage. After delivery and payment the buyer gave notice of defects of the powder. The seller conceded the defect but invoked its general conditions which restricted the amount of damages insofar differing from the buyer's general conditions. The Court held that neither the seller's nor the buyer's standard terms applied. Both the knock out rule (Restgültigkeitslehre) and the last shot rule (Theorie des letzten Wortes) would result in that consequence: the knock out rule would exclude the conflicting terms; under the last shot rule the principle of good faith (Art. 7 par. 1 CISG) would yield the same result because the seller could not expect that the buyer would accept the seller's conditions to which it had objected via its own conditions. Anyhow, the effect of the decision is the result regularly achieved by the knock out rule.

In the BGH case both parties had fully performed their primary contractual duties and indeed this is the clearest indication that the parties regarded the divergences in their standard terms as no hindrance to the conclusion of their contract. In this phase of the contract the question is no longer whether there was a contract but only what was its contents.[40] As stated above it is much more convincing then to exclude the conflicting terms altogether than to accept those which were brought in last (with the pre-mentioned exception, however, that one party had clearly surrendered to the conditions of the other party).[41] [page 195]

b) Partial performance by both parties

It may be questioned whether the above result is also acceptable if both parties have only started performance or if only one party has fully performed whereas the other began with performance. Thus far, there seems to be no relevant case law on this question. However, it is hardly doubtful that the outcome must be the same as if both parties had fully performed as long as the preparatory acts evidence sufficiently the assent to the contract. For this result also Art. 18 par. 3 CISG gives some interpretative support. The provision states that "performing an act, such as one relating to the dispatch of the goods or the payment of the price" may indicate sufficient assent to the contract. An act "relating to" the performance does therefore not only mean the act of full performance but includes also preparatory acts, for instance the opening of a letter of credit,[42] start of production or the like.[43] It is only necessary that the act is an unambiguous sign of consent.

c) Performance by one party

If only one party has started or effected performance it becomes more doubtful whether this act suffices to indicate both parties' assent to the contract despite conflicting standard terms.[44] It is the performing party's assent. But the other party's assent? If the performing party is the one who wants to rely on the own conditions in order to deny the conclusion of a contract it follows rather clearly from the principle of good faith (Art. 7 par. 1 CISG) that the party is precluded from relying on the own conditions.[45] If redress to the own standard terms would be allowed in such a case this would offend a general principle of the Convention, namely the ban of venire contra factum proprium.[46] The same result should follow if the performing party tries to rely on the own conditions in order to object against the standard conditions of the other party. However, also the other party cannot expect that without more the performing party has waived its general terms and [page 196] surrendered to the other party's conditions. This argument relied on by the BGH in the milkpowder-case [47] is valid also here. The outcome is therefore again the same: even if only one party starts performance and if there is no clear indication that this party has intentionally accepted the other party's conditions then again the knock out rule should apply and exclude the conflicting terms.

d) Range of the knock out

It might be doubtful how far the knock out reaches, which conflicting general terms are knocked out. Only those which are directly irreconcilable for the concrete dispute? Or further terms? The milkpowder-case [48] raised also this issue. In that case there was a direct conflict between the general terms of the seller and the buyer on liability. But there were also further terms on the whole regulation of defects contained in the standard conditions of the buyer. They were favourable to the seller who therefore wanted to rely on them. The German Federal Court decided -- correctly in my view -- that the seller could not have the best of two worlds: not the disadvantages of the buyer's conditions but the advantages of those conditions. The Court held that the knock out rule excluded the full set of rules of both general terms which regulated the entire complex of warranty for delivery of defective goods though not all of these rules were a direct issue of the case at hand. The reason for this decision is that the general conditions generally form a balanced net of rules. This balance would be disturbed if only one provision of the concerned complex of rules would be excluded while the rest would still remain applicable. A party is therefore not allowed to practise cherry-picking from the general conditions of the other party when the knock out rule applies. The rule knocks out the whole complex in issue.

Not rarely there is no direct contradiction between the standard terms but the terms of one party contain a certain solution while the terms of the other party are silent on that point. Unless the intentions of the parties and the interpretation of the term require another solution this discrepancy will also be covered by the knock out rule since it is also a divergence between the terms of both sides. [page 197]

2. Assent to the Contract in Other Forms than by Performance?

Can the parties express their consent to a contract despite materially conflicting standard terms also in other forms than by starting performance? Or is performance or part performance the only valid indication of assent to a contract that suffers from the defect that some of the general conditions which the parties wanted to include are irreconcilable? The question is interwoven with the question whether the knock out rule can or should be applied as well in the phase before performance. Again, Art. 18 par. 3 CISG can be of some help. As already mentioned the provision speaks of "indicate assent by performing an act, such as one relating to the dispatch of the goods or the payment of the price". This formulation draws mainly on acts of performance but evidently not exclusively. Also other conduct that is capable of indicating assent to the contract can suffice. Admittedly, it is difficult to imagine such other conduct. But for instance, acts, declarations, notices towards third persons are clearly imaginable from which the intention to be bound can be inferred.

3. Application of the Knock out Rule also before the Performance Phase?

The main question remains, however, whether without any even partial performance the knock out rule should apply when the parties have reached agreement on the essentials of the contract while their included standard terms differ in certain respects. As far as this question is at all discussed with respect to the CISG a positive answer is partly favoured,[49] partly disfavoured.[50] The UNIDROIT Principles, the Principles of European Contract Law and the UCC all follow the knock out rule irrespective whether or not the parties have already started performance of the contract.[51] Taking into account that general conditions serve the aim to provide for a precautionary and subsidiary set of rules in case of dispute over the contract it makes good sense that after an agreement over the essentials a dissent over matters of 'second class terms' should generally not wreck the contract. On the other [page 198] hand, the parties must remain free to indicate that the inclusion of their standard forms is an essential condition for the conclusion of the contract. The central question then is how and when 'second class terms' do become 'first class terms'. In this respect a general principle of the Convention should be reminded. The CISG obliges the parties to give each other fair and reasonable information in due time even in situations not specifically mentioned in the Convention.[52] It is therefore necessary that a party who insists on its standard terms as essential for the conclusion of the contract makes that clear before the formation of the contract and in a form whose seriousness cannot be overlooked by the other party. As both the UNIDROIT Principles and the Principles of European Contract Law suggest a mere standard form information will not do.[53] The clear indication requires more than that. Only if it is clearly mentioned among the other essentialia negotü will this indication suffice.[54]

VI. FINAL REMARKS

In 1986 Jan Hellner [55] very clearly saw that Art. 19 CISG which makes an acceptance with material modifications always a counter-offer does not fit for the battle of forms. The time is ripe to follow this insight. [page 200]

FOOTNOTES

* The following works are cited in an abbreviated form: Wilhelm Albrecht Achilles, Kommentar zum UN-Kaufrechtsübereinkommen (CISG), in: Ensthaler (ed.), Gemeinschafteskommentar zum Handelsgesetzbuch mit UN-Kaufrecht (7th ed. 2007); Bernard Audit, La vente internationale de marchandises (1990); Heinz Georg Bamberger/Herbert Roth (eds.), Kommentar zum Bürgerlichen Gesetzbuch vol. 1 (2nd ed. 2007) (- Ingo Saenger); Herbert Bernstein/Joseph Lookofsky, Understanding the CISG in Europe (2nd ed. 2003); Cesare Massimo Bianca/Michael Joachim Bonell (eds.), Commentary on the International Sales Law. The 1980 Vienna Sales Convention (1987); Christoph Brunner, UN-Kaufrecht -- CISG (2004); Franco Ferrari/Harry Flechtner/Ron Brand (eds.), The Draft UNCITRAL Digest and Beyond: Cases, Analysis and Unresolved Issues in the U.N. Sales Convention (2004), Rolf Herber/Beate Czerwenka, Internationales Kaufrecht (1991); Vincent Heuzé, La vente internationale de marchandises -- Droit uniforme (2nd ed. 2000); John O. Honnold, Uniform Law for International Sales under the 1980 United Nations Convention (3rd 1999); Heinrich Honsell (ed.), Kommentar zum UN-Kaufrecht. Übereinkommen der Vereinten Nationen über Verträge über den internationalen Warenkauf (CISG) (1997); Münchener Kommentar zum Bürgerlichen Gesetzbuch vol. 3 (4th ed. 2004); Münchener Kommentar zum Handelsgesetzbuch vol. 6 (2004); Burghard Piltz, Internationales Kaufrecht (1993); Gert Reinhart, UN-Kaufrecht. Kommentar zum Ubereinkommen der Vereinten Nationen vom 11. April 1980 über Verträge über den internationalen Warenkauf (1991); Peter Schlechtriem, Internationales UN-Kaufrecht (4th ed. 2007); Peter Schlechtriem/Ingeborg Schwenzer (eds.), Kommentar zum Einheitlichen UN-Kaufrecht -- CISG -- (4th ed. 2004); Schulthei, Allgemeine Geschüftsbedingungen im UN-Kaufrecht (2004); Michael Schwimann (ed.), ABGB Praxiskommentar vol. 4 (3rd ed. 2006) (- Willibald Posch); Hans-Theodor Soergel (ed.), Bürgerliches Gesetzbuch, vol. 13: CISG (13th ed. 2000); Julius von Staudinger (- Ulrich Magnus), Kommentar zum Bürgerlichen Gesetzbuch mit Einführungsgesetz und Nebengesetzen. Wiener UN-Kaufrecht (CISG) (2005); Wolfgang Witz/Hanns-Christian Salger/Manuel Lorenz, International Einheitliches Kaufrecht (2000).

1. See Art. 2.1.22 UNIDROIT Principles; Art. 2:209 Lando Principles.

2. As to most recent court decisions compare for instance: Kantonsgericht des Kantons Zug, Internationales Handelsrecht -- International Commercial Law (IHR) 2005,119 m. Anm. Fountoulakis; OLG Köln IHR 2006, 147; Kantonsgericht des Kantons Zug IHR 2006, 158; OLG München IHR 2007, 30; LG Coburg IHR 2007, 117 m. Anm. Piltz; OLG Linz IHR 2007, 123.

3. In: Sarcevic/Volken (eds.), Dubrovnik Lectures (1986) 335 et seq.

4. Although Hellner (supra fn. 3) 336 had primarily in mind terms like the INCOTERMS etc. when he spoke of standard form contracts.

5. As shown by the cases cited in fn. 2.

6. See expressly in this sense Oberlandesgericht Koblenz (Germany -- OLG) WM 1984, 1347 et seq.; also Kühl/Hingst, in: Festschrift Herber (2000) 57.

7. See also Pilar Perales Viscasillas, Pace International Law Review 10 (1998) 106.

8. It must however be born in mind that the form of jurisdiction and also arbitration clauses is governed by legislation outside the CISG (see in particular Art. 23 Brussels I Regulation and Art. II UN Convention on the Recognition and Enforcement of Foreign Arbitral Awards).

9. See Lando/Beale (eds.), The Principles of European Contract Law Parts I and II (2000) 181; also Forte, in: MacQueen/Zimmermann (eds.), European Contract Law: Scots and South African Perspectives (2006) 98 et seq.

10. See Bundesgerichtshof (Germany -- BGH) IHR 2002, 14; Oberster Gerichtshof (Austria -- OGH), Zeitschrift fur Rechtsvergleichung (ZfRV) 2004, 110; OLG Düsseldorf IHR 2005,24; Kramer, in: Festschrift Welser (2004) 553; Luig, Der internationale Vertragsschluss (2003) 237; Pilar Perales Viscasillas, in: Felemegas (ed.), An International Approach to the Interpretation of the United Nations Convention on Contracts for the International Sale of Goods (1980) as Uniform Sales Law (2007) 318; Piltz IHR 2004, 137; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Schwimann/Posch Art. 19 n. 7; Staudinger/Magnus Art. 19 n. 20; but contrary for instance Rechtbank Zutphen (Netherlands), Nederlands Internationaal Privaatrecht (NIPR) 1998 nr. 110; Rechtbank Rotterdam NIPR 2002 nr. 147; also Ebenroth, Juristische Blätter (JBl.) 1986,686; Vergne Am. J. Comp. L. 33 (1985)256 et seq.; probably also Del Duca, The Journal of Law and Commerce 25 (2005/2006) 146; indifferently Hellner (fn. 3) 342 ("To this question I have no answer.").

11. See BGHZ 149, 113 = IHR 2002, 16 and thereon Pilar Perales Viscasillas, Vindobona Journal 2002,217 et seq.; further Achilles Art. 24 n. 7; Bamberger/Roth/Saenger Art. 14 n. 7; MünchKomm HGB/Ferrari Art. 14 n. 39; Piltz IHR 2004, 133 et seq.; Schlechtriem/Schwenzer/Schlechtriem Art. 14 n. 16; Staudinger/Magnus Art. 14 n. 41; but contra Berger, in: Festschrift Horn (2006) 3 et seq.; Kindler, in: Festschrift Heldrich (2005) 225 et seq.

12. See for instance, Chateau des Charmes Wines Ltd. v. Sabaté USA Inc., 328 F. 3d 328.

13. If the offeror objects in time no contract is concluded; see Herber/Czerwenka Art. 19 n. 15; Honnold n. 168; MünchKomm HGB/Ferrari Art. 19 n. 24; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 18; Staudinger/Magnus Art. 19 n. 14.

14. Cour de cassation, Droit d'affaires 1998, 1694; Bianca/Bonell/Farnsworth Art. 19 n. 2.8; Brunner Art. 19 n. 3; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Staudinger/Magnus Art. 19 n. 17.

15. See Filanto SpA v. Chilewich International Corp., 789 F. Supp. 1229 (S.D. NY, 1992); Bianca/Bonell/Farnsworth Art. 19 n. 2.8; Hellner (fn. 3) 340 et seq.; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Staudinger/Magnus Art. 19 n. 17.

16. In this sense Cour de cassation, Droit d'affaires 1998, 1694.

17. See thereto MünchKomm HGB/Ferrari Art. 19 n. 11 et seq.; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 9; Staudinger/Magnus Art. 19 n. 19.

18. See references in preceding fn.

19. OGH ZfRV 1997, 204; Cour de cassation, Recueil Dalloz Sirey (D.) 1995, 289; OLG Naumburg Transp-IHR 2000,22; Bamberger/Roth/Saenger Art. 19 n. 5; Bernstein/Lookofsky 60; MünchKomm HGB/Ferrari Art. 19 n. 10; Piltz § 3 n. 87; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 8; Soergel/Luderitz/Fenge Art. 19 n. 3; Staudinger/Magnus Art. 19 n. 16; but contra for instance Heuzé n. 186; MünchKomm BGB/Gruber Art. 19 n. 7; Reinhart Art. 19 n. 6; Witz/Salger/Lorenz Art. 19 n. 9; doubting Audit n. 70.

20. See Cour d'appel Paris CLOUT n. 158 (changes concerning the price regarded as immaterial); for further examples see Ferrari/Flechtner/Brand 594 et seq.

21. MünchKomm HGB/Ferrari Art. 19 n. 13; Soergel/Lüderitz/Fenge Art. 19 n. 3; Staudinger/Magnus Art. 19 n. 19.

22. See OGH ZfRV 1997,204; Bamberger/Roth/Saenger Art. 19 n. 5; MünchKomm BGB/Gruber Art. 19 n. 8; MünchKomm HGB/Ferrari Art. 19 n. 13; Pilar Perales Viscasillas Pace Int. L. Rev. 14 (2002) 155; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 8; Staudinger/Magnus Art. 19 n. 19.

23. Landgericht Baden-Baden (Germany -- LG), Recht der Internationalen Wirtschaft (RIW) 1992, 62 (notice period fixed with 30 days: held to correspond to the legal period).

24. It is provided for in Art. 6 CISG.

25. See also Schlechtriem n. 92.

26. See with respect to the CISG in particular Forte, in: MacQueen/Zimmermann (supra fn. 9) 115 ("quite simply not an acceptable solution "); Honnold n. 170.3; Kramer, in: Festschrift Gauch (2004) 493 et seq.; idem, in: Festschrift Welser (2004) 556 et seq.; Kröll/Hennecke RIW 2001, 737 et seq.; Pilar Perales Viscasillas Pace Int. L. Rev. 1998, 97 et seq.; Schlechtriem, in Festschrift Herber (2000) 36 et seq.; Vergne, American Journal of Comparative Law 1985, 233 et seq.

27. See also Kramer, in: Festschrift Welser (2004) 554.

28. Hellner (fn. 3) 342 with reference also to Lord Denning's judgment in the English case Butler Machine Tool Co. Ltd. v. Ex-Cell-O Corporation (England) Ltd. [1979] 1 All E. R. 965.

29. In the same sense OLG Linz IHR 2007,123; Achilles Art. 19 n. 5; Kramer, in: Festschrift Welser (2004) 556 et seq.; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n.20; Staudinger/Magnus Art. 19 n. 24 et seq.

30. Such inferral is only admissible if one of the parties retracts the own standard terms or does clearly no longer insist on them during the negotiation of the contract; compare for such a case OLG Linz IHR 2007, 123 (in that case the buyer referred in its first order to its general conditions but then never came back to them although the other party in all following correspondance insisted on its own conditions).

31. In this sense for instance Cour de cassation, Droit d'affaires 1998, 1694; OLG Köln IHR 2006,147 (though in ambiguous language); OLG Linz IHR 2007,123; Amtsgericht Kehl (AG -- Germany) NJW-RR 1996, 565.

32. See Achilles Art. 19 n. 5; van Alstine, Fehlender Konsens beim Vertragsabschluss nach dem einheitlichen UN-Kaufrecht (1995) 220 et seq.; Audit n. 71; Bamberger/Roth/Saenger Art. 19 n. 3; Bernstein/Lookofsky 61 et seq.; Brunner Art. 4 n. 44; Karollus 70 et seq.; Kramer, in: Festschrift Welser (2004) 556 et seq.; Kühl/Hingst, in: Festschrift Herber (2000) 56 et seq; MünchKomm BGB/Gruber Art. 19 n. 24; Schlechtriem n. 92; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Schwenzer/Mohs IHR 2006, 244; Soergel/Luderitz/Fenge Art. 19 n. 5; Staudinger/Magnus Art. 19 n. 24; cautiously also Meeusen, in: van Houtte/Erauw/Wautelet (eds.), Het Weens Koopverdrag (1997) 93 et seq.

33. See for instance Herber/Czerwenka Art. 19 n. 18; Honsell/Schnyder/Straub Art. 19 n.37 et seq. (with some exceptions); Moccia Fordham Int. L. J. 13 (1989-1990) 659; MünchKomm HGB/Ferrari Art. 19 n. 15; Pilar Perales Viscasillas Pace Int. L. Rev. 2002, 157 et seq. (though with some reluctance); eadem, in: Felemegas (supra fn. 10) 318; Reinhart Art. 19 n. 8.

34. See for instance (though the language is not always unambiguous) BGHZ 149, 113 = IHR 2002, 16; Cour de cassation, Droit d'affaires 1998, 1694; OLG Köln IHR 2006, 147; OLG Linz IHR 2007, 123; AG Kehl NJW-RR 1996, 565.

35. See for instance OLG Hamm Transp-IHR 1999, 24; leaving the question undecided OGH IHR 2002, 74.

36. Art. 2.1.22 UNIDROIT Principles. See thereto the explanation given by UNIDROIT, UNIDROIT Principles (2004) 71 et seq. (a standard term is normally no clear indication of the unwillingness to be bound by a contract without the own standard terms).

37. Art. 2:209 Principles of European Contract Law (they provide explicitly that such indication cannot be made by way of general conditions).

38. See in particular BGHZ 149, 113 = IHR 2002, 16; Achilles Art. 19 n.5; van Alstine, Fehlender Konsens beim Vertragsabschluss nach dem einheitlichen UN-Kaufrecht (1995) 220 et seq.; Audit n. 71; Bamberger/Roth/Saenger Art. 19 n. 3; Bernstein/Lookofsky 60 et seq.; Brunner Art. 4 n. 44; Karollus 70 et seq.; Kramer, in: Festschrift Welser (2004) 556 et seq.; Luig (supra fn. 10) 243 et seq. (with certain qualifications); MünchKomm BGB/Gruber Art. 19 n. 24; Schlechtriem n. 92; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Schwenzer/ Mohs IHR 2006,244; Soergel/Lüderitz/Fenge Art. 19 n. 5; Staudinger/Magnus Art. 19 n. 24.

39. BGHZ 149,113 = IHR 2002, 16 and thereon Pilar Perales Viscasillas, Vindobona Journal 2002,217 et seq.;

40. See in particular Bernstein/Lookofsky 61 et seq.; Kramer, in: Festschrift Welser (2004) 556 et seq.; Luig (supra fn. 10) 238 et seq.; MünchKomm BGB/Gruber Art. 19 n. 24; Schlechtriem n. 92; Schlechtriem/Schwenzer/Schlechtriem Art. 19 n. 20; Schwenzer/Mohs IHR 2006,244.

41. See supra under IV. 3.

42. Magellan International Corp. v. Salzgitter Handels GmbH, 76 F. Supp. 2d 919 (N.D. Ill., 1999).

43. Compare Bianca/Bonell/Farnsworth Art. 18 n.2.2; Schlechtriem/Schwenzer/Schlechtriem Art. 18 n. 7; Staudinger/Magnus Art. 18 n. 11.

44. The question is rarely discussed; but compare Schlechtriem, in: Festschrift Herber (2000) 44 et seq. (in principle both parties must have started performance, but exceptions).

45. Similarly Schlechtriem, in: Festschrift Herber (2000) 45.

46. See OLG Karlsruhe, Betriebsberater (BB) 1998, 392; OLG Köln CLOUT n. 168; Herber/Czerwenka Art. 7 n. 6; Piltz § 2 n. 170; Staudinger/Magnus Art. 7 n. 25 with further references.

47. BGHZ 149,113 = IHR 2002,16.

48. See preceding fn.

49. Kröll/Hennecke RIW 2001, 742.

50. MünchKomm BGB/Gruber Art. 19 n. 27.

51. For a comparison of these regulations with the CISG see in particular: Forte, in: MacQueen/Zimmermann (supra fn. 10) 98 et seq.; Pilar Perales Viscasillas, Pace International Law Review 10 (1998) 97 et seq.; eadem, Pace Int. L. Rev. 13 (2001) 371 et seq.; eadem, Pace Int. L. Rev. 14 (2002) 153 et seq.

52. BGHZ 149, 118; Audit n.51; Honnold n.100; Schlechtriem/Schwenzer/Ferrari Art.7 n. 54; Staudinger/Magnus Art. 7 n. 48.

53. See UNIDROIT, UNIDROIT Principles (2004) 71 et seq. and the examples given there; Art. 2:209 Principles of European Contract Law which explicitly provides this rule.

54. Doubts to such form of indication are expressed by Schlechtriem, in: Festschrift Herber (2000) 44.

55. Hellner (supra fn. 3) 342.