Dyfyniad APA

Richard W Ojakangas. (1976). The earth: Past and present. New York: McGraw-Hill.

Dyfyniad Arddull Chicago

Richard W Ojakangas. The Earth: Past and Present. New York: McGraw-Hill, 1976.

Dyfyniad MLA

Richard W Ojakangas. The Earth: Past and Present. New York: McGraw-Hill, 1976.

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