KELLIL, Rabah. HYPERGROUPS AND FUZZY SETS ASSOCIATED MODULO A SUBGROUP. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 36, p. 719–730, 2016. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6490. Acesso em: 16 aug. 2026.