ArtemovichO. D. “On Locally Graded Groups With Minimality Condition for a Certain System of Nonhypercentral Subgroups”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 10 (October 25, 1999): 1425–1430. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4742.