48 C.F.R. §§ 52.232-2
As prescribed in 32.111(a)(2), insert the following clause, as appropriately modified with respect to payment due dates in accordance with agency regulations, in solicitations and contracts when a fixed-price research and development contract is contemplated:
Payments Under Fixed-Price Research and Development Contracts (APR 1984)
The Government shall pay the Contractor, upon submission of proper invoices or vouchers, the prices stipulated in this contract for work delivered or rendered and accepted, less any deductions provided in this contract. Unless otherwise specified, payment shall be made upon acceptance of any portion of the work delivered or rendered for which a price is separately stated in the contract.
(End of clause)
48 C.F.R. §§52.232-2