Zirnstein, G. (1982). Charles Darwin. Teubner.
Lua i Stíl Chicago (17ú heag.)Zirnstein, Gottfried. Charles Darwin. Leipzig: Teubner, 1982.
Lua MLA (8ú heag.)Zirnstein, Gottfried. Charles Darwin. Teubner, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.