Cita APA (7th ed.)
Marshall, R., & Rosskopf, A. (2001). AGS Earth Science. American Guidance Service inc.
Cita Chicago (17th ed.)
Marshall, Robert, i Allen Rosskopf. AGS Earth Science. Minnesota: American Guidance Service inc, 2001.
Cita MLA (9th ed.)
Marshall, Robert, i Allen Rosskopf. AGS Earth Science. American Guidance Service inc, 2001.
Atenció: Aquestes cites poden no estar 100% correctes.