(2006). 2006: World development indicators. Washington, D.C: The World Bank.
Trích dẫn kiểu Chicago2006: World Development Indicators. Washington, D.C: The World Bank, 2006.
MLA引文2006: World Development Indicators. Washington, D.C: The World Bank, 2006.
警告:這些引文格式不一定是100%准確.