Dömösi, Pál, and Zoltán Ésik. “On Homomorphic Simulation of Automata by α0-Products”. Acta Cybernetica 8, no. 4 (January 1, 1988): 315–323. Accessed May 11, 2025. https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3346.