He, Hong-yan, Hui-ping, Zhang, and Hong-fang Luo. “Design of Multi-Level Teaching System Based on Association Rule Mining”. International Journal of Emerging Technologies in Learning (iJET) 11, no. 11 (November 29, 2016): pp. 43–48. Accessed January 22, 2022. https://online-journals.org/index.php/i-jet/article/view/6252.