SATIRAD, Akarachai; IAMPAN, Aiyared. Fuzzy sets in fully UP-semigroups. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 42, p. 539–558, 2019. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/7211. Acesso em: 27 oct. 2026.