Zuzuk, L. I. 1997. “Construction of Nonnilpotent Biprimary Dispersible Groups With Metacyclic Subgroups of Nonprimary Index”. Ukrains’kyi Matematychnyi Zhurnal 49 (6), 849–851. https://umj.imath.kiev.ua/index.php/umj/article/view/5071.