WVC 46 - 2 - 202
§46-2-202. 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
(a) By course of performance, course of dealing, or usage of
trade (section 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.