Press, F., & Siever, R. (1974). Earth. W. H. Freeman.
Lua i Stíl Chicago (17ú heag.)Press, Frank, agus Raymond Siever. Earth. San Francisco, Calif: W. H. Freeman, 1974.
Lua MLA (9ú heag.)Press, Frank, agus Raymond Siever. Earth. W. H. Freeman, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.