Csákány, Béla. “A Form of the Zermelo—von Neumann Theorem under Minimal Assumptions”. Acta Cybernetica 15, no. 3 (January 1, 2002): 321-325. Accessed April 27, 2024. https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3581.