Zuzuk, L. I. “Finite Nondispersible Groups All Subgroups of Which With Nonprimary Index Are Metacyclic”. Ukrains’kyi Matematychnyi Zhurnal 47, no. 6 (June 25, 1995): 755–759. Accessed April 7, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/5468.