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.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)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.
Trích dẫn kiểu MLA (xuất bản lần thứ 9)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.
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