27 C.F.R. § 19.729
(a) For each shipment or other removal of fuel alcohol from the alcohol fuel plant premises, the consignor proprietor must prepare a commercial invoice, sales slip, or similar document that shows:
(b) The consignor proprietor must retain in its records a copy of the document described in paragraph (a) of this section.
(26 U.S.C. 5181)