MONK, D. On Equational Classes of Algebraic Versions of Logic I. MATHEMATICA SCANDINAVICA, [S. l.], v. 27, p. 53–71, 1970. DOI: 10.7146/math.scand.a-10987. Disponível em: https://www.mscand.dk/article/view/10987. Acesso em: 19 may. 2024.