KovalenkoV. I. “Locally Graded Groups With Normal Nonmetacyclic Subgroups”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 1 (January 25, 2007): 133–135. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3296.