Volume 20, numbers 1-50; January 5, 1973; January 12, 1973; January 19, 1973; January 26, 1973; February 2, 1973; February 9, 1973; February 16, 1973; February 23, 1973; March 2, 1973; March 9, 1973; March 16, 1973; March 23, 1973; March 30, 1973;...
Volume 18, numbers 1-48; January 8, 1971; January 15, 1971; January 22, 1971; January 29, 1971; February 5, 1971; February 12, 1971; February 19, 1971; March 5, 1971 (Special Issue); March 12, 1971; March 19, 1971; March 26, 1971; April 2, 1971; April...
Volume 19, numbers 1-49; January 7, 1972; January 14, 1972; January 21, 1972; February 4, 1972; February 11, 1972; February 18, 1972; February 25, 1972; March 3, 1972; March 10, 1972; March 17, 1972; March 24, 1972; March 31, 1972; April 7, 1972; April...
Volume 21, numbers 1-47; January 4, 1974; January 11, 1974; January 19, 1974; January 25, 1974; February 1, 1974; February 8, 1974; February 15, 1974; February 22, 1974; March 1, 1974; March 8, 1974; March 15, 1974; March 22, 1974; March 29, 1974;...
Volume 25, numbers 1-50; January 6, 1978; January 13, 1978; January 20, 1978; January 27, 1978; February 3, 1978; February 10, 1978; February 17, 1978; February 24, 1978; March 3, 1978; March 10, 1978; March 17, 1978; March 24, 1978; March 31, 1978;...
Volume 23, numbers 1-50; January 9, 1976; January 16, 1976; January 23, 1976; January 30, 1976; February 6, 1976; February 13, 1976; February 20, 1976; February 27, 1976; March 5, 1976; March 12, 1976; March 19, 1976; March 26, 1976; April 2, 1976;...
Volume 24, numbers 1-50; January 7, 1977; January 14, 1977; January 21, 1977; January 28, 1977; February 4, 1977; February 11, 1977; February 18, 1977; February 25, 1977; March 4, 1977; March 11, 1977; March 18, 1977; March 25, 1977; April 1, 1977;...
Volume 22, numbers 1-47 and 17 1/2; January 3, 1975; January 10, 1975; January 17, 1975; January 24, 1975; January 31, 1975; February 7, 1975; February 14, 1975; February 21, 1975; February 28, 1975; March 7, 1975; March 14, 1975; March 21, 1975; March...