Pham Minh Chuan, Le Hoang Son, Vu Khanh Quy, and Nguyen Dinh Chien. “A NOVEL HYBRID META-HEURISTIC ALGORITHM BASED ON BLACK HOLE AND HARMONY SEARCH FOR FUZZY CLUSTERING PROBLEM”. UTEHY Journal of Science and Technology, Vol. 27, Oct. 2020, pp. 47-53, http://tapchi.utehy.edu.vn/index.php/jst/article/view/388.