48 CFR § 52.216-23
Execution and Commencement of Work
November 17, 2020
As prescribed in 16.603-4(b)(1), insert the following clause in solicitations and contracts when a letter contract is contemplated, except that it may be omitted from letter contracts awarded on SF 26:
Execution and Commencement of Work (APR 1984)
The Contractor shall indicate acceptance of this letter contract by signing three copies of the contract and returning them to the Contracting Officer not later than ___ [insert date]. Upon acceptance by both parties, the Contractor shall proceed with performance of the work, including purchase of necessary materials.