Dyfyniad APA

Thornbury, W. D. (1969). Principles of geomorphology (2nd edition.). Wiley.

Dyfyniad Arddull Chicago

Thornbury, William D. Principles of Geomorphology. 2nd edition. New York: Wiley, 1969.

Dyfyniad MLA

Thornbury, William D. Principles of Geomorphology. 2nd edition. Wiley, 1969.

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