Thảo, Nguyễn Xuân, and Nguyễn Văn Định. “Rough Picture Fuzzy Set and Picture Fuzzy Topologies”. Journal of Computer Science and Cybernetics 31, no. 3 (September 14, 2015): 245. Accessed April 26, 2024. https://vjs.ac.vn/index.php/jcc/article/view/5046.