MOHAMMADZADEH, E.; MOHAMMADZADEH, F. α-NILPOTENT GROUPS DERIVED FROM HYPERGROUPS WITH ξ∗-RELATION. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 39, p. 97–106, 2018. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6951. Acesso em: 7 oct. 2026.