Romanovsky , A. V., and A. V. Sementovsky. “Existence of Normal Complement to the Hall Subgroup ”. Ukrains’kyi Matematychnyi Zhurnal 44, no. 6 (July 7, 1992): 851–853. Accessed February 17, 2026. https://umj.imath.kiev.ua/index.php/umj/article/view/8023.