Dyfyniad APA

Press, F. (2004). Understanding earth (4th ed.). W.H. Freeman and Company.

Dyfyniad Arddull Chicago

Press, Frank. Understanding Earth. 4th ed. New York: W.H. Freeman and Company, 2004.

Dyfyniad MLA

Press, Frank. Understanding Earth. 4th ed. W.H. Freeman and Company, 2004.

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