(e)(4) Contractor access to DLA sources of supply is limited to DLA-managed national stock numbered (NSN) or part numbered (P/N) items provided to DoD customers specifically authorized under a DLA contract that will use a DLA supply source. The contract should specify any ceiling quantities that may apply to an item. The rationale supporting the decision to authorize use of a DLA source of supply will be coordinated with the managing contracting activity, documented in writing for each NSN or P/N, signed by the contracting officer authorizing use of the DLA supply source, approved by the CCO, and included in the contract file.