Giang, N.L., Tùng, N.T. and Thi, V. Đức 2012. A new method for attribute reduction to imcomplete decision table based on metric. Journal of Computer Science and Cybernetics. 28, 2 (Oct. 2012), 129–140. DOI:https://doi.org/10.15625/1813-9663/28/2/2494.