APA
United Nations Development Programme, World Resources Institute, . (1989). Natural endowments. Washington, D. C: World Resources Institute.
Chicago
United Nations Development Programme, World Resources Institute, . 1989. Natural endowments. Washington, D. C: World Resources Institute.
Harvard
United Nations Development Programme, World Resources Institute, . (1989). Natural endowments. Washington, D. C: World Resources Institute.
MLA
United Nations Development Programme, World Resources Institute, . Natural endowments. Washington, D. C: World Resources Institute. 1989.