Clark, R. (1961). The universe: Plan or accident? Muhlenberg Press.
Dyfyniad Arddull ChicagoClark, Robert. The Universe: Plan or Accident? Philadelphia: Muhlenberg Press, 1961.
Dyfyniad MLAClark, Robert. The Universe: Plan or Accident? Muhlenberg Press, 1961.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.