VincenziG., KurdachenkoL. A., and RussoA. “On Some Groups All Subgroups of Which Are Nearly Pronormal”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 10 (October 25, 2007): 1331–1338. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3392.