Dyfyniad APA

Plummer, C. C., Carlson, D. H., & Hammersley, L. (2013). Physical geology (14th ed.). McGraw-Hill.

Dyfyniad Arddull Chicago

Plummer, Charles C., Diane H. Carlson, and Lisa Hammersley. Physical Geology. 14th ed. New York: McGraw-Hill, 2013.

Dyfyniad MLA

Plummer, Charles C., et al. Physical Geology. 14th ed. McGraw-Hill, 2013.

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