Dyfyniad APA

Sanders, J. E. (1981). Principles of physical geology. John willey &sons.

Dyfyniad Arddull Chicago

Sanders, John E. Principles of Physical Geology. New york: John willey &sons, 1981.

Dyfyniad MLA

Sanders, John E. Principles of Physical Geology. John willey &sons, 1981.

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