Ludman, A., & Coch, N. K. (1982). Physical geology. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Ludman, Allan, agus Nicholas K. Coch. Physical Geology. New York: McGraw-Hill, 1982.
Lua MLA (9ú heag.)Ludman, Allan, agus Nicholas K. Coch. Physical Geology. McGraw-Hill, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.