KURDACHENKO, L. A.; SOULES, P. Groups with Hypercyclic Proper Quotient Groups. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 55, n. 4, p. 470–478, 2003. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3920. Acesso em: 6 dec. 2025.