(810 ILCS 5/2-202) (from Ch. 26, par. 2-202)

Sec. 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 (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.

(Source: P.A. 95-895, eff. 1-1-09.)