Aimmanee, Pakinee, and Thanaruk Theeramunkong. “Improving the Retrieval Performance by Using the Distance-Based Bigrams”. ECTI Transactions on Electrical Engineering, Electronics, and Communications 8, no. 1 (August 1, 2009): 106–112. accessed August 29, 2026. https://ph02.tci-thaijo.org/index.php/ECTI-EEC/article/view/172043.