Okla. Stat. tit. 12, § 1752B
The venue of civil actions instituted under small claims procedure for the collection of an open account or for the collection of any note or other instrument of indebtedness shall be, at the option of the plaintiff or plaintiffs in either of the following:
Laws 1971, HB 1056, c. 249, § 1, eff. October 1, 1971.