Okla. Stat. tit. 11 § 39-109
After the governing body creates a district, the governing body may proceed, either to make the improvement by force accounting, or call for sealed bids on the proposed improvement, or where the district comprises land owned by a single party, developer, or other legal entity that has petitioned for the creation of the district, contract with that single party, developer or other legal entity to make the improvement for future dedication or other conveyance to the city; provided, however, in the case of the districts created pursuant to Section 39-103.1 of this title and except as otherwise provided in this section, the governing body may contract for said services without calling for sealed bids or force accounting. The notice shall state the manner of payment to the contractor and whether the contractor will be paid in money, in bonds or in a proportion of money and bonds for making the improvement. The governing body may to the extent that funds are available authorize payments to the contractor during the construction of the improvement provided that the payments do not exceed the amount of work completed and that ten percent (10%) of such payments shall be retained by the city pending final acceptance by the city of the improvement. The term "improvement" as used in this section and Sections 101 through 136 of Title 61 of the Oklahoma Statutes shall not include any services or maintenance authorized and provided pursuant to Section 39-103.1 of this title.
Okla. Stat. tit. 11, § 39-109