27 C.F.R. § 26.174
(b) Details of records. Each person intending to claim drawback on eligible articles brought into the United States shall maintain permanent records showing the following data:
(c) Evidence of taxpayment of distilled spirits. All shipments of eligible articles from Puerto Rico to the United States shall be supported by the vendor's commercial invoice which must bear a certification as to taxpayment by the person who determined or paid the tax, and include the following information:
(e) Retention of records. Each drawback claimant shall retain for a period of not less than three years all records required by this subpart, all commercial invoices or shipping documents, and all bills of lading received evidencing receipt and tax determination of the spirits. In addition, a copy of each approved formula returned to the manufacturer of eligible articles shall be retained for not less than three years from the date he files his last claim for drawback under the formula. The records, forms, and formulas shall be readily available during regular business hours for examination by appropriate TTB officers.
(Approved by the Office of Management and Budget under control number 1512-0494)
[T.D. ATF-263, 52 FR 46594, Dec. 9, 1987, as amended by T.D. ATF-451, 66 FR 21669, May 1, 2001]