PETRUKHIN, Y. Natural Deduction for Four-Valued both Regular and Monotonic Logics. Logic and Logical Philosophy, [S. l.], v. 27, n. 1, p. 53–66, 2017. DOI: 10.12775/LLP.2017.001. Disponível em: https://apcz.umk.pl/LLP/article/view/LLP.2017.001. Acesso em: 27 apr. 2024.