CHUBARYAN, A. On the Hierarchies of Some Propositional Systems for Classical and Non-classical Logics. Mathematical Problems of Computer Science, [S. l.], v. 38, p. 95–96, 2021. Disponível em: http://mpcs.sci.am/index.php/mpcs/article/view/579. Acesso em: 3 may. 2024.