D.C. Mun. Regs. tit. 1, § 1703
1703.1 Any contract entered into after the effective date of this chapter shall contain the following:
1703.2 A contract for meat or meat food products, perishable agricultural commodities, or any other contract with a payment due date based on delivery, shall require that a proper invoice be submitted with each shipment. Supplies under these contracts shall not be deemed delivered until the later of the date of actual delivery or the date of receipt of a proper invoice.
SOURCE: Final Rulemaking published at 35 DCR 8131, 8132-33 (November 18, 1988).