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

49A1 [Buyer's right to avoid contract (grounds for avoidance): fundamental breach of contract];

75A1 [Damages established by substitute transaction after avoidance: resale by aggrieved seller];

78A [Interest on delay in receiving price or any other sum in arrears];

80A [Failure of performance caused by other party (party causing non-performance): loss of rights]