Dyfyniad APA

(2000). Earth and its resources. New York: McGraw-Hill School division.

Dyfyniad Arddull Chicago

Earth and Its Resources. New York: McGraw-Hill School division, 2000.

Dyfyniad MLA

Earth and Its Resources. New York: McGraw-Hill School division, 2000.

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