Okla. Stat. tit. 21, § 21-499: Defenses to charges of perjury

(1) Upon accusation of a charge of perjury by single statement,

as defined in Section 491 of Title 21, it is a defense that the

statement is true.

(2) Upon accusation of a charge of perjury by contradictory

statements, as defined in Section 496 of Title 21, it is a defense

that the accused at the time he made each statement believed the

statement was true.