Baryshovets, P. P. “On Complementability of Nonmetacyclic Subgroups in Finite $A$-Groups”. Ukrains’kyi Matematychnyi Zhurnal 53, no. 12 (December 25, 2001): 1600–1606. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4381.