Cita APA (7th ed.)

Press, F., & Siever, R. (1997). Understanding earth (2a. ed.). W. H. Freeman.

Cita Chicago (17th ed.)

Press, Frank, i Raymond Siever. Understanding Earth. 2a. ed. Nueva York: W. H. Freeman, 1997.

Cita MLA (9th ed.)

Press, Frank, i Raymond Siever. Understanding Earth. 2a. ed. W. H. Freeman, 1997.