Section, Pub. L. 88–452, title II, § 221, Aug. 20, 1964, 78 Stat. 524; Pub. L. 89–253, § 30(b), Oct. 9, 1965, 79 Stat. 979; Pub. L. 89–794, title II, § 218, Nov. 8, 1966, 80 Stat. 1464, extended the program through June 30, 1970, and provided that only such sums may be appropriated as the Congress might authorize by law, prior to the general amendment of Part D of this subchapter by Pub. L. 90–222, title I, § 104, Dec. 23, 1967, 81 Stat. 705. See section 2837 of this title.