57A-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 performance, course of dealing or usage of trade (§57A-1-303); 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.
Source: SL 1966, ch 150, §2-202; SDCL §57-3-4; SL 2008, ch 259, §26.