Cita APA

Joseph Wood Krutch. (1968). Grand Canyon: Today and its yesterday. New York: Apollo.

Chicago Style Citation

Joseph Wood Krutch. Grand Canyon: Today and Its Yesterday. New York: Apollo, 1968.

Cita MLA

Joseph Wood Krutch. Grand Canyon: Today and Its Yesterday. New York: Apollo, 1968.

Atenció: Aquestes cites poden no estar 100% correctes.