L. A. Shemetkov, “Complements and supplements to normal subgroups of finite groups”, Ukr. Mat. Zhurn., vol. 23, no. 5, pp. 678–689, Sep. 1971, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8340