HOLUBOWSKI, W. Note on Symmetric Words in Metabelian Groups. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 7, p. 1013–1015, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4140. Acesso em: 6 dec. 2025.