FAR 



5152.101 - Using Part 5152.

(b)  Numbering.

(2)  Provisions or clauses that supplement the FAR.

(ii)

(A)  The numbers of clauses or provisions published in the Federal Register and codified in Title 48, Code of Federal Regulations (CFR), shall be preceded by 51, the Chapter number assigned to the Army by the CFR staff.

(iii)  Army major commands must number supplemental provisions or clauses using four-digit sequential numbers in the 5000 series. Their subordinate commands or contracting offices shall use numbers in the 4000 series.