APA
World Bank, . (2001). World development indicators 2001. Washington, D.C: World Bank.
Chicago
World Bank, . 2001. World development indicators 2001. Washington, D.C: World Bank.
Harvard
World Bank, . (2001). World development indicators 2001. Washington, D.C: World Bank.
MLA
World Bank, . World development indicators 2001. Washington, D.C: World Bank. 2001.