Giang, Nguyễn Long, Nguyễn Thanh Tùng, and Vũ Đức Thi. 2012. “A New Method for Attribute Reduction to Imcomplete Decision Table Based on Metric”. Journal of Computer Science and Cybernetics 28 (2):129-40. https://doi.org/10.15625/1813-9663/28/2/2494.