VINH, L. X. On the supremum, infimum of two incomparable elements of non-homogeneous hedge algebras. Journal of Computer Science and Cybernetics, [S. l.], v. 20, n. 3, p. 242–256, 2012. DOI: 10.15625/1813-9663/20/3/1487. Disponível em: https://vjs.ac.vn/index.php/jcc/article/view/1487. Acesso em: 2 may. 2024.