Keeton, W. T. (1980). Biological Science.
Lua i Stíl Chicago (17ú heag.)Keeton, Willian T. Biological Science. 1980.
Lua MLA (9ú heag.)Keeton, Willian T. Biological Science. 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.