Okla. Stat. tit. 61, § 103.2
The governing body of any political subdivision of this state may duly appoint as its agent any individual or individual of a legal entity, with whom the political subdivision has duly entered into a public contract pursuant to law, to make purchases necessary for carrying out the public contract.
Laws 1981, SB 141, c. 243, § 2, emerg. eff. June 23, 1981.