ONISHCHUK , V. A.; SYSAK , Ya. P. Local nilpotent groups satisfying a weak condition of minimality or maximality for subgroups of fixed degree of nilpotency . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 3, p. 384–389, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8107. Acesso em: 11 apr. 2025.