U.C.C. Sect. 2-202 Final Written Expression; Parol or Extrinsic Evidence

Terms with respect to which the confirmatory memoranda of the parties agree or which are otherwise set forth in a writing intended by the parties as a final expression of their agreement with respect to such terms as are included therein may not be contradicted by evidence of any prior agreement or of a contemporaneous oral agreement but may be explained or supplemented

(a) by course of dealing or usage of trade (Section 1-205) or by course of performance (Section 2-208); and

(b) by evidence of consistent additional terms unless the court finds the writing to have been intended also as a complete and exclusive statement of the terms of the agreement.