Okla. Stat. tit. 11 § 51-107
Within five (5) days from the date of the request for arbitration referred to in Section 51-106 of this title, the bargaining agent and the corporate authorities shall each select and name one arbitrator and shall immediately thereafter notify each other in writing of the name and address of the person so selected.
The two arbitrators so selected and named shall, within five (5) days from and after the expiration of the five-day period hereinabove mentioned, agree upon and select a third arbitrator. If, on the expiration of the period allowed therefor, the arbitrators are unable to agree upon the selection of a third arbitrator, the bargaining agent and the corporate authorities shall request the Federal Mediation and Conciliation Service to provide a list of five arbitrators. Within five (5) days after receipt of the list of arbitrators from the Federal Mediation and Conciliation Service, the two arbitrators already selected shall alternately strike the name of one arbitrator from the list of five until one name remains, with the employer making the first strike from said list. The third arbitrator, whether selected as a result of an agreement between the two arbitrators previously selected or selected from the list provided by the Federal Mediation and Conciliation Service, shall act as chairman of the arbitration board.
Okla. Stat. tit. 11, § 51-107