Definition of Strong Equality of Tautologies and Universal System for Various Propositional Logics. Armenian Journal of Mathematics, [S. l.], v. 1, n. 2, p. pp. 30–36, 2008. Disponível em: https://armjmath.sci.am/index.php/ajm/article/view/25.. Acesso em: 7 may. 2024.