Johnson, P. H. (1968). The survival of the fittest. Macmillan.
Lua i Stíl Chicago (17ú heag.)Johnson, Pamela Hansford. The Survival of the Fittest. London, Melbourne [etc.]: Macmillan, 1968.
Lua MLA (8ú heag.)Johnson, Pamela Hansford. The Survival of the Fittest. Macmillan, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.