Section 227.7009-1 - Required clauses(a) Covenant Against Contingent Fees. Insert the clause at FAR 52.203-5.(b) Gratuities. Insert the clause at FAR 52.203-3.(c) Assignment of Claims. Insert the clause at FAR 52.232-23.(d) Disputes. Pursuant to FAR 33.014, insert the clause at FAR 52.233-1.(e) Non-Estoppel. Insert the clause at 252.227-7000.56 FR 36389, July 31, 1991, as amended at 61 FR 50454, Sept. 26, 1996