KLEINFELD, E.; KLEINFELD, M. SIMPLE RINGS WITH $(R,R,R)$ IN LEFT NUCLEUS. Tamkang Journal of Mathematics, [S. l.], v. 30, n. 1, p. 35–37, 1999. DOI: 10.5556/j.tkjm.30.1999.4203. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4203. Acesso em: 8 may. 2024.