Press, F., & Siever, R. (1998). Understanding earth: Frank Press, Raymond Siever (2nd ed.). W.H.Freeman and Company.
Cita Chicago (17th ed.)Press, Frank, i Raymond Siever. Understanding Earth: Frank Press, Raymond Siever. 2nd ed. New York: W.H.Freeman and Company, 1998.
Cita MLA (9th ed.)Press, Frank, i Raymond Siever. Understanding Earth: Frank Press, Raymond Siever. 2nd ed. W.H.Freeman and Company, 1998.
Atenció: Aquestes cites poden no estar 100% correctes.