Demeny, P. G. (1981). The North-South income gap: A demographic perspective. Population Council.
Lua i Stíl Chicago (17ú heag.)Demeny, Paul George. The North-South Income Gap: A Demographic Perspective. New York: Population Council, 1981.
Lua MLA (9ú heag.)Demeny, Paul George. The North-South Income Gap: A Demographic Perspective. Population Council, 1981.
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