Putilov, S. V., and N. S. Chernikov. “On π-Solvable and Locally π-Solvable Groups With Factorization”.
Ukrains’kyi Matematychnyi Zhurnal 53, no. 6 (June 25, 2001): 840–846. Accessed April 26, 2025.
https://umj.imath.kiev.ua/index.php/umj/article/view/4304.