Okla. Stat. tit. 2, § 17-15
The affairs of the association shall be managed by a board of not less than five or more than twenty-one directors to be elected by the members with such qualifications as may be provided for in the Articles of Incorporation or bylaws. All of the directors shall be members of the association or officers, directors or members of member association.
Laws 1937, p. 266, § 15 eff. emerg. May 22, 1937.