Plummer, C. (1985). Introduction to physical geology. Macmillan.
Lua i Stíl Chicago (17ú heag.)Plummer, Charles. Introduction to Physical Geology. New York: Macmillan, 1985.
Lua MLA (9ú heag.)Plummer, Charles. Introduction to Physical Geology. Macmillan, 1985.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.