United Nations Department of International Economic and Social Affairs. (1991). Concise report on the world population situation in 1991, with a special emphasis on age structure. United Nations.
芝加哥风格引文United Nations Department of International Economic and Social Affairs. Concise Report on the World Population Situation in 1991, with a Special Emphasis on Age Structure. New York: United Nations, 1991.
MLA引文United Nations Department of International Economic and Social Affairs. Concise Report on the World Population Situation in 1991, with a Special Emphasis on Age Structure. United Nations, 1991.
警告：这些引文格式不一定是100％准确.