Kongreß of philosophy. (1973). Proceedings of the XVth [fifteenth] World Congress of Philosophy: 17th to 22nd september 1973, Varna (Bulgaria). Sofia Pr..
Čikaški stil citiranja (17. izdanje)Kongreß of philosophy. Proceedings of the XVth [fifteenth] World Congress of Philosophy: 17th to 22nd September 1973, Varna (Bulgaria). Sofia: Sofia Pr., 1973.
MLA način citiranja (8. izdanje)Kongreß of philosophy. Proceedings of the XVth [fifteenth] World Congress of Philosophy: 17th to 22nd September 1973, Varna (Bulgaria). Sofia Pr., 1973.
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