KLEINFELD, ERWIN, and MARGARET KLEINFELD. “SIMPLE RINGS WITH $(R,R,R)$ IN LEFT NUCLEUS”. Tamkang Journal of Mathematics 30, no. 1 (March 1, 1999): 35–37. Accessed May 8, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4203.