Khan, J., J. P. Li, G. A. Khan, A. Malik, S. Parveen, and M. Shahid. “A Survey on Rough Set Theory and Their Extension For Data Mining”. Asian Journal For Convergence In Technology (AJCT) ISSN -2350-1146, Apr. 2019, http://asianssr.org/index.php/ajct/article/view/759.