Hồ, Nguyễn Cát, and Lê Xuân Vinh. “On Some Properties of Ordering Relation in Non-Homogeneous Hedge Algebras”. Journal of Computer Science and Cybernetics 19, no. 4 (July 27, 2012): 373–381. Accessed April 4, 2026. https://cip.vast.vn/jcc/article/view/1546.