APA
United Nations. Department of Economic and Social Affairs, . (1973). World population prospects as assessed in 1968. New York: United Nations.
Chicago
United Nations. Department of Economic and Social Affairs, . 1973. World population prospects as assessed in 1968. New York: United Nations.
Harvard
United Nations. Department of Economic and Social Affairs, . (1973). World population prospects as assessed in 1968. New York: United Nations.
MLA
United Nations. Department of Economic and Social Affairs, . World population prospects as assessed in 1968. New York: United Nations. 1973.