Ge, Chao, and Jiaqi Xie. “Application of Grey Forecasting Model Based on Improved Residual Correction in the Cost Estimation of University Education”. International Journal of Emerging Technologies in Learning (iJET) 10, no. 8 (December 14, 2015): pp. 30–33. Accessed May 6, 2024. https://online-journals.org/index.php/i-jet/article/view/5215.