Naturally Ordered Abundant Semigroups for which each Idempotent has a Greatest Inverse. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 4, n. 3, p. 210–220, 2011. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/1240.. Acesso em: 2 may. 2024.