AS 45.12.202: Final written expression: parol or extrinsic evidence.

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

(1) by course of dealing or usage of trade or by course of performance; 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.