Dyfyniad APA

Plummer, C. C., Carlson, D. H., & Hammersley, L. (2016). Physical geology (Fifteenth edition, International edition.). McGraw-Hill/Education, Inc.

Dyfyniad Arddull Chicago

Plummer, Charles C., Diane H. Carlson, and Lisa Hammersley. Physical Geology. Fifteenth edition, International edition. New York, NY: McGraw-Hill/Education, Inc, 2016.

Dyfyniad MLA

Plummer, Charles C., et al. Physical Geology. Fifteenth edition, International edition. McGraw-Hill/Education, Inc, 2016.

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