Okla. Stat. tit. 11, § 11-17-114: Vendor invoices and contract estimates - Payment

procedures - Uniform jackets.

To facilitate the payment of vendor invoices and contract

estimates the municipal finance officer may design a uniform jacket

to be used by all departments and divisions of the municipality

whereon shall be provided summarized information relative to the

enclosed invoices or contract estimates, together with a space for

the approval of the head of the department or division approving

said vendor invoices or contract estimates for payment. Vendor

invoices and contract estimates may be accepted by the municipality

in lieu of the claim form previously required in the same manner as

commercial invoices are paid. If utilized, vendor invoices and

contract estimates shall be filed with the department or division

receiving the merchandise or services in the same manner as invoices

are filed with commercial firms. Upon receipt of invoices or

contract estimates the head of the department or division or his

authorized agent, may approve said documents for payment by

executing a certificate of delivery or acceptance of the goods or

services. Whereupon, the authorized official of said agency may

approve said invoices or contract estimates for payment by enclosing

the invoice or contract estimate in a jacket provided for such

purpose and affixing his or her approval in the space provided on

the jacket.