CZELAKOWSKI, J. Logics and operators. Logic and Logical Philosophy, [S. l.], n. 3, p. 87–100, 2003. DOI: 10.12775/LLP.1995.005. Disponível em: https://apcz.umk.pl/LLP/article/view/LLP.1995.005. Acesso em: 19 apr. 2024.