YEN, C.-T. RINGS WITH $(x,R,x)$ AND $(N +NR,R)$ IN THE LEFT NUCLEUS. Tamkang Journal of Mathematics, [S. l.], v. 23, n. 3, p. 247–251, 1992. DOI: 10.5556/j.tkjm.23.1992.4548. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4548. Acesso em: 25 apr. 2024.