Ariz. Rev. Stat. § 47-2202 : UNIFORM COMMERCIAL CODE — SALES — FORM, FORMATION AND READJUSTMENT OF CONTRACT —2202 - 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:

1. By course of performance, course of dealing or usage of trade (section 47-1303) ; and

2. 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.

A.R.S. § 47-2202