ANSARI, Moin A.; KOAM, Ali N.A.; HAIDER, Azeem. Rough set theory applied to UP-algebras. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 42, p. 388–402, 2019. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/7228. Acesso em: 27 oct. 2026.