(德文) Szilard, Leo (1929). "Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen (On the reduction of entropy in a thermodynamic system by the intervention of intelligent beings)". Zeitschrift für Physik. 53 (11–12): 840–856. Bibcode:1929ZPhy...53..840S. doi:10.1007/bf01341281. cited in Bennett 1987. English translation available as NASA document TT F-16723 published 1976 (页面存档备份,存于互联网档案馆)
(德文) Szilard, Leo (1929). "Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen (On the reduction of entropy in a thermodynamic system by the intervention of intelligent beings)". Zeitschrift für Physik. 53 (11–12): 840–856. Bibcode:1929ZPhy...53..840S. doi:10.1007/bf01341281. cited in Bennett 1987. English translation available as NASA document TT F-16723 published 1976 (页面存档备份,存于互联网档案馆)