APA
United Nations D. o. E. a. S. A., . (2013). World economic and social survey, 2013: Sustainable development challenges. New York: United Nations.
Chicago
United Nations Department of Economic and Social Affairs, . 2013. World economic and social survey, 2013: Sustainable development challenges. New York: United Nations.
Harvard
United Nations D. o. E. a. S. A., . (2013). World economic and social survey, 2013: Sustainable development challenges. New York: United Nations.
MLA
United Nations Department of Economic and Social Affairs, . World economic and social survey, 2013: Sustainable development challenges. New York: United Nations. 2013.