Cita APA (7th ed.)

Thornbury, W. D. (1969). Principles of geomorphology (2nd ed.). John Wiley & Sons.

Cita Chicago (17th ed.)

Thornbury, William D. Principles of Geomorphology. 2nd ed. New York: John Wiley & Sons, 1969.

Cita MLA (9th ed.)

Thornbury, William D. Principles of Geomorphology. 2nd ed. John Wiley & Sons, 1969.