Vorob’ev, N. T., Y. Nanying, and Z. Shuya. “On the Problem of Frattini Duality in the theory of Fitting Classes”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 71, no. 7, July 2019, pp. 922-9, https://umj.imath.kiev.ua/index.php/umj/article/view/1486.