Vincenzi, G., L. A. Kurdachenko, and A. Russo. “On Some Groups All Subgroups of Which Are Nearly Pronormal”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 10 (October 25, 2007): 1331–1338. Accessed April 26, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3392.