APA (7th ed.) Zitazioa
Levin, H. L. (1990). Contemporary physical geology (3rd ed.). Saunders College Pub..
Chicago Style (17th ed.) Zitazioa
Levin, Harold L. Contemporary Physical Geology. 3rd ed. Philadelphia, Pa.: Saunders College Pub., 1990.
MLA (9th ed.) Zitazioa
Levin, Harold L. Contemporary Physical Geology. 3rd ed. Saunders College Pub., 1990.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.