Mississippi Code
Part 2 - . Formation and Construction of Lease Contract
§ 75-2A-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:
By course of dealing or usage of trade or by course of performance; and
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.