Cita APA (7th ed.)
Marshak, S., & Prothero, D. R. (2001). Earth: Portrait of a planet. Norton.
Cita Chicago (17th ed.)
Marshak, Stephen, i Donald R. Prothero. Earth: Portrait of a Planet. New York: Norton, 2001.
Cita MLA (9th ed.)
Marshak, Stephen, i Donald R. Prothero. Earth: Portrait of a Planet. Norton, 2001.
Atenció: Aquestes cites poden no estar 100% correctes.