A certificate by the Commissioner of Customs  stating the amount of an expenditure made from funds advanced and certifying that the confidential nature of the transaction involved renders it inadvisable to specify the details thereof or impracticable to furnish the payee’s receipt shall be a sufficient voucher for the sum expressed to have been expended.
19 U.S. Code § 2078. Certification of reason for advance
Reference to Commissioner of Customs deemed to be reference to Commissioner of U.S. Customs and Border Protection pursuant to section 802(d)(2) of Pub. L. 114–125, set out as a note under section 211 of Title 6, Domestic Security.
Amendment by Pub. L. 91–513 effective on first day of seventh calendar month that begins after the day immediately preceding the date of enactment of Pub. L. 91–513, which was approved on Oct. 27, 1970, see section 1105(a) of Pub. L. 91–513, set out as an Effective Date note under section 951 of Title 21, Food and Drugs.
Prosecutions for any violation of law occurring, and civil seizures or forfeitures and injunctive proceedings commenced, prior to the effective date of amendment of this section by section 1102 of Pub. L. 91–513 not to be affected or abated by reason thereof, see section 1103 of Pub. L. 91–513, set out as a note under section 171 of Title 21, Food and Drugs.
For transfer of functions, personnel, assets, and liabilities of the United StatesCustoms Service of the Department of the Treasury, including functions of the Secretary of the Treasury relating thereto, to the Secretary of Homeland Security, and for treatment of related references, see sections 203(1), 551(d), 552(d), and 557 of Title 6, Domestic Security, and the Department of Homeland Security Reorganization Plan of November 25, 2002, as modified, set out as a note under section 542 of Title 6. For establishment of U.S. Customs and Border Protection in the Department of Homeland Security, treated as if included in Pub. L. 107–296 as of Nov. 25, 2002, see section 211 of Title 6, as amended generally by Pub. L. 114–125, and section 802(b) of Pub. L. 114–125, set out as a note under section 211 of Title 6.
For transfer of functions of other officers, employees, and agencies of Department of the Treasury, with certain exceptions, to Secretary of the Treasury, with power to delegate, see Reorg. Plan No. 26 of 1950, §§ 1, 2, eff. July 31, 1950, 15 F.R. 4935, 64 Stat. 1280, 1281, set out in the Appendix to Title 5, Government Organization and Employees.
 See Change of Name note below.