Regularity on Variants of Transformation Semigroups that Preserve an Equivalence Relation. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 15, n. 4, p. 2116–2126, 2022. DOI: 10.29020/nybg.ejpam.v15i4.4596. Disponível em: https://ejpam.com/index.php/ejpam/article/view/4596.. Acesso em: 3 jul. 2024.