2009. General Provisions of the UNIDROIT Principles: Arts. 1.1 (Freedom of contract), 1.2 (No form required), 1.3 (Binding character of contract), 1.4 (Mandatory rules), 1.5 (Exclusion or modification by the parties) and 1.10 (Notice), 1.11 (Definitions), 1.12 (Computation of time set by parties), in: Stefan Vogenauer / Jan Kleinheisterkamp eds., Commentary on the UNIDROIT Principles of International Commercial Contracts, (PICC), Oxford University Press (2009) 111-139 and 202-214