25B [Definition of fundamental breach: substantial deprivation of expectation, etc.];

40B [Seller's knowledge of non-conformity (seller fails to disclose known non-conformity): seller loses right to rely on articles 38 and 39];

51B1 [Non-conformity of part of goods (avoidance of entire contract): must be based on fundamental breach of contract as a whole];

81C [Effect of avoidance on obligations: restitution by each party of benefits received]