Okla. Stat. tit. 11 § 22-153
Any municipality may issue its obligations in the manner set out in the Oklahoma Municipal Utility Revenue Bond Act in order to finance, or to refinance, all or a part of the cost of the acquisition, purchase or construction of, or the making of improvements to any public utility owned or to be owned exclusively by said municipality, and said obligations shall be payable from and secured by the revenues resulting from the operation of the municipality's revenue-producing public utilities or any part thereof. Provided, nothing herein shall authorize or be construed to authorize a municipality to create a lien or mortgage on, or a security interest in or with respect to such public utility or utilities to secure said obligations. The obligations, when issued and delivered, shall state on the face thereof that the revenue indebtedness or contractual obligations created thereby are limited obligations of the municipality payable from and secured by a lien and charge on the revenues of funds pledged for their payment by the governing body of the municipality and shall not constitute a general indebtedness of the municipality, nor shall it invoke or require the imposition of the general taxing power of such municipality.
Okla. Stat. tit. 11, § 22-153