Ramsey, W. L. (1965). Modern earth science. Ren Inc.
Lua i Stíl Chicago (17ú heag.)Ramsey, William L. Modern Earth Science. Q. C: Ren Inc, 1965.
Lua MLA (9ú heag.)Ramsey, William L. Modern Earth Science. Ren Inc, 1965.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.