Okla. Stat. tit. 70 § 2206
Except as to revenues paid directly to a trustee under the provisions of subsection (e) of Section 3 hereof, all income and revenues derived from the operation of the building shall be deposited as collected in a fund to be applied solely to the payment of the principal of and interest on the bonds and, to the extent so provided in the resolution authorizing the bonds, to the payment of the cost of maintaining and operating the building and the establishment of reserves for such purpose. As principal and interest become due from time to time the Treasurer shall, not less than fifteen (15) days prior to the payment date, transmit to the paying agent for the bonds money from said fund in an amount sufficient to pay the principal or interest so falling due. Said fund and the money therein is hereby irrevocably pledged to such purposes.
Okla. Stat. tit. 70, § 2206