Dyfyniad APA

World Resources Institute, United Nations Environment Programme, & United Nations Development Programme. (1990). World resources. Oxford University Press.

Dyfyniad Arddull Chicago

World Resources Institute, United Nations Environment Programme, and United Nations Development Programme. World Resources. New York: Oxford University Press, 1990.

Dyfyniad MLA

World Resources Institute, et al. World Resources. Oxford University Press, 1990.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.