G. Vincenzi, L. A. Kurdachenko, and A. Russo, “On some groups all subgroups of which are nearly pronormal”, Ukr. Mat. Zhurn., vol. 59, no. 10, pp. 1331–1338, Oct. 2007, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3392