SAWA, Zdeněk; JANČAR, Petr. Behavioural Equivalences on Finite-State Systems are PTIME-hard. Computing and Informatics, [S. l.], v. 24, n. 5, p. 513–528, 2012. Disponível em: https://www.cai.sk/ojs/index.php/cai/article/view/397. Acesso em: 30 apr. 2025.