Charіn V. S. On groups of finite rank. II. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 18, n. 3, p. 85–96, 1966. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8739. Acesso em: 5 dec. 2025.