Perera, P. (1989). Emerging issues of population aging in Sri Lanka. Economic and Social Commission for Asia and the Pacific, United Nations.
Chicago-referens (17:e uppl.)Perera, P.D.A. Emerging Issues of Population Aging in Sri Lanka. Bangkok: Economic and Social Commission for Asia and the Pacific, United Nations, 1989.
MLA-referens (9:e uppl.)Perera, P.D.A. Emerging Issues of Population Aging in Sri Lanka. Economic and Social Commission for Asia and the Pacific, United Nations, 1989.
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