OBERHELMAN, David D. Stanford Encyclopedia of Philosophy2001311Principal Editor, Edward N. Zalta. Stanford Encyclopedia of Philosophy. Stanford, CA: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University 1999; updated every three months. Internet URL: http://plato.stanford.edu, ISSN1095-5054 Gratis Last visited: May 2001. Reference Reviews. 2001-06, roč. 15, čís. 6, s. 9–9. Dostupné online [cit. 2021-12-13]. ISSN0950-4125. DOI10.1108/rr.2001.15.6.9.311.
Stanford Encyclopedia of Philosophy. plato.stanford.edu [online]. [cit. 2021-12-13]. Dostupné online.
OBERHELMAN, David D. Stanford Encyclopedia of Philosophy2001311Principal Editor, Edward N. Zalta. Stanford Encyclopedia of Philosophy. Stanford, CA: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University 1999; updated every three months. Internet URL: http://plato.stanford.edu, ISSN1095-5054 Gratis Last visited: May 2001. Reference Reviews. 2001-06, roč. 15, čís. 6, s. 9–9. Dostupné online [cit. 2021-12-13]. ISSN0950-4125. DOI10.1108/rr.2001.15.6.9.311.
BERENDZEN, J. C. Stanford Encyclopedia of Philosophy (Fall 2013 edition) [online]. Stanford: 2013. Dostupné online.
OBERHELMAN, David D. Stanford Encyclopedia of Philosophy2001311Principal Editor, Edward N. Zalta. Stanford Encyclopedia of Philosophy. Stanford, CA: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University 1999; updated every three months. Internet URL: http://plato.stanford.edu, ISSN1095-5054 Gratis Last visited: May 2001. Reference Reviews. 2001-06, roč. 15, čís. 6, s. 9–9. Dostupné online [cit. 2021-12-13]. ISSN0950-4125. DOI10.1108/rr.2001.15.6.9.311.