Cartesian product of interval-valued fuzzy ideals in ordered semigroup. Journal of Prime Research in Mathematics, [S. l.], v. 12, n. 1, p. 120 – 129, 2016. Disponível em: https://jprm.sms.edu.pk/index.php/jprm/article/view/124. Acesso em: 4 feb. 2026.