Optional Form 307, Contract Award, Standard Form (SF) 26, Award/Contract, or SF 33, Solicitation, Offer and Award, may be used to award negotiated contracts in which the signature of both parties on a single document is appropriate. Note however, if using the SF 26 for a negotiated procurement, block 18 is not to be used. If these forms are not used, the award document shall incorporate the agreement and award language from the OF 307.
48 C.F.R. §15.509