Okla. Stat. tit. 74 § 581
That any department of the state government or any state institution may contract with any other department of state government or institution having under its control the personal services, labor and equipment, machinery or other facilities to perform needed work for or on behalf of the state or its subdivisions, department or institutions, when such work may be performed by the use of machinery, equipment, material and/or labor of the department or institution under its control contracting to furnish such service by the use of such facilities of its own, or those of any institution of the state under its control. The department or institution or subdivision obtaining and receiving such services shall pay or otherwise compensate the department or institution performing the work for the fair value thereof, including the cost of material used and proper compensation by payment or exchange for any personal services, labor, equipment and material employed in performing such work or services; which said funds shall be deposited in a special depository account to be kept separately from all other collections and may be expended by the departments, subdivisions or institutions performing the services by voucher issued by said department or institution and drawn on the State Treasurer; provided, however, that when such services are performed by any department or institution having a revolving fund, such payments may be credited to and become a part of such revolving fund.
Okla. Stat. tit. 74, § 581