WANG, Jun Tao; QIAN, Ting; SHE, Yan Hong. Characterizations of obstinate filters in semihoops. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 42, p. 851–862, 2019. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/7182. Acesso em: 27 oct. 2026.