Clark, R. (1961). The universe: Plan or accident? Muhlenberg Press.
Chicago-čujuhus (17. p.)Clark, Robert. The Universe: Plan or Accident? Philadelphia: Muhlenberg Press, 1961.
MLA-čujuhus (9. p.)Clark, Robert. The Universe: Plan or Accident? Muhlenberg Press, 1961.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.