Delaware Code
Part 2. Formation and Construction of Lease Contract
§ 2A-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 or by course of performance; 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.

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