27 C.F.R. § 40.167
Sec. 202, Pub. L. 85-859, 68A Stat. 1417 ( 26 U.S.C. 5703 ); sec. 202, Pub. L. 85-859, 72 Stat. 1423, as amended ( 26 U.S.C. 5741 ); (Aug. 16, 1954, ch. 736, 68A Stat. 775, as amended ( 26 U.S.C. 6302 )); 26 U.S.C. 7805 (68A Stat. 917, as amended)