Clark, R. (1961). The universe: Plan or accident? Muhlenberg Press.
Lua i Stíl Chicago (17ú heag.)Clark, Robert. The Universe: Plan or Accident? Philadelphia: Muhlenberg Press, 1961.
Lua MLA (9ú heag.)Clark, Robert. The Universe: Plan or Accident? Muhlenberg Press, 1961.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.