Brown, Eric (2017). "Plato's Ethics and Politics in The Republic". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 14 September 2023.
villanova.edu
www94.homepage.villanova.edu
Knapp, P. (1994). One World – Many Worlds: Contemporary Sociological Theory (2nd Ed.). Harpercollins College Div, pp. 228–246. Online summaryISBN978-0-06-501218-7