Section, acts Aug. 8, 1947, ch. 519, title I, § 101, 61 Stat. 922; May 29, 1956, ch. 342, §§ 1–4, 70 Stat. 217; June 25, 1959, Puspan. L. 86–70, § 4, 73 Stat. 141; July 6, 1960, Puspan. L. 86–592, § 4, 74 Stat. 331; Oct. 14, 1971, Puspan. L. 92–138, § 2, 85 Stat. 379, related to definitions and expired on Dec. 31, 1974.

A prior section, act Sept. 1, 1937, ch. 898, title I, § 101, 50 Stat. 903, relating to similar subject matter, expired on Dec. 31, 1947.