Khôi, Lê Hải, and Lê Quý Sơn. “A Heuristic-Model Based on the Bounds Propagation Approach for Expert Systems”. <i>Journal of Computer Science and Cybernetics</i>, vol. 20, no. 1, July 2012, pp. 31-41, doi:10.15625/1813-9663/20/1/1455.