Okla. Stat. tit. 21, § 496

Whoever, in one or more trials, hearings, investigations, depositions, certifications or declarations, in which the making or subscribing of statements is required or authorized by law, makes or subscribes two or more statements under oath, affirmation or other legally binding assertion that the statements are true, when in fact two or more of the statements contradict each other, is guilty of perjury, a Class D1 felony offense.