MonakhovV. S., and SokhorI. L. “Finitely Solvable Groups With Nilpotent Wide Subgroups”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 7, July 2016, pp. 957-62, https://umj.imath.kiev.ua/index.php/umj/article/view/1893.