Cita APA (7th ed.)
Powers, W. E. (1966). Physical Geography. Appleton-Century-Crofts.
Cita Chicago (17th ed.)
Powers, William Edwards. Physical Geography. New York: Appleton-Century-Crofts, 1966.
Cita MLA (9th ed.)
Powers, William Edwards. Physical Geography. Appleton-Century-Crofts, 1966.
Atenció: Aquestes cites poden no estar 100% correctes.