Okla. Stat. tit. 19, § 1713

Any monies received or expended by the district must be accounted for by fund and account. Each district shall prepare a budget for the general fund and for other funds as the board may require pursuant to this act. The board shall determine the district's needs for sinking fund purposes, pursuant to this act and Section 9C of Article X of the Constitution of the State of Oklahoma, and include these requirements in the debt service fund budget for the budget year.