Cita APA (7th ed.)

Spencer, E. W. (1993). Physical geology. Addison-Wesley Pub. Co..

Cita Chicago (17th ed.)

Spencer, Edgar Winston. Physical Geology. Reading, Mass.: Addison-Wesley Pub. Co., 1993.

Cita MLA (9th ed.)

Spencer, Edgar Winston. Physical Geology. Addison-Wesley Pub. Co., 1993.