Leet, L. D., & Leet, F. J. (1961). The world of geology. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Leet, Lewis Don, agus Florence J. Leet. The World of Geology. New York: McGraw-Hill, 1961.
Lua MLA (9ú heag.)Leet, Lewis Don, agus Florence J. Leet. The World of Geology. McGraw-Hill, 1961.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.