APA
United Nations. Department of International Economic and Social Affairs, . (1990). Step-by-step guide to the estimation of child mortality. New York: United Nations.
Chicago
United Nations. Department of International Economic and Social Affairs, . 1990. Step-by-step guide to the estimation of child mortality. New York: United Nations.
Harvard
United Nations. Department of International Economic and Social Affairs, . (1990). Step-by-step guide to the estimation of child mortality. New York: United Nations.
MLA
United Nations. Department of International Economic and Social Affairs, . Step-by-step guide to the estimation of child mortality. New York: United Nations. 1990.