Παραπομπή APA

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

Παραπομπή Chicago Style

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

Παραπομπή MLA

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