Khan, Muhammad, Shehzad Khalid, and Furqan Aziz. “Graph Clustering Based Size Varying Rules for Lifelong Topic Modelling”. Global Journal of Computer Sciences: Theory and Research 8, no. 3 (December 29, 2018): 111-119. Accessed June 18, 2019. https://sproc.org/ojs/index.php/gjcs/article/view/4021.