LAVRENYUK, Ya. V.; SUSHCHANSKII, V. I. Lattice of normal subgroups of a group of local isometries of the boundary of a spherically homogeneous tree. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 10, p. 1350–1356, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3249. Acesso em: 5 dec. 2025.