On Idempotent Elements. AL-Rafidain Journal of Computer Sciences and Mathematics, [S. l.], v. 6, n. 3, p. 49–56, 2009. DOI: 10.33899/csmj.2009.163820 . Disponível em: https://csmj.uomosul.edu.iq/index.php/csmj/article/view/36457. Acesso em: 25 jun. 2026.