TREBENKO, D. Ya.; CHERNIKOV, N. S. Quotient Groups of Groups of Certain Classes. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 52, n. 8, p. 1141–1143, 2000. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4519. Acesso em: 5 dec. 2025.