Jamali, Shahram, and Yahya Dorostkar Navaei. “A Two-Level Product Recommender for E-Commerce Sites by Using Sequential Pattern Analysis”. International Journal of Integrated Engineering 8, no. 1 (April 1, 2016). Accessed May 7, 2024. https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/1330.