GHANE, F.H.; HAMED, Z. UPPER TOPOLOGICAL GENERALIZED GROUPS. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 27, p. 321–332, 2010. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/5800. Acesso em: 24 apr. 2026.