D. MAHMOOD, R.; A. HADID, D. On Simple Singular N-Flat Modules. AL-Rafidain Journal of Computer Sciences and Mathematics, [S. l.], v. 10, n. 3, p. 13–20, 2013. DOI: 10.33899/csmj.2013.163522 . Disponível em: https://csmj.uomosul.edu.iq/index.php/csmj/article/view/36699. Acesso em: 2 nov. 2025.