Dyfyniad APA

(2000). World Resousces, 1990 - 91: People and Ecosystems : the fraying web of life. Washington, D.C: World Resources Institute.

Dyfyniad Arddull Chicago

World Resousces, 1990 - 91: People and Ecosystems : The Fraying Web of Life. Washington, D.C: World Resources Institute, 2000.

Dyfyniad MLA

World Resousces, 1990 - 91: People and Ecosystems : The Fraying Web of Life. Washington, D.C: World Resources Institute, 2000.

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