Areef, Ali. “Correction for Multicollinearity Between the Explanatory Variables to Estimation by Using the Principal Component Method ”. University of Thi-Qar Journal of Science 2, no. 2 (April 27, 2010): 145–151. Accessed April 3, 2025. https://jsci.utq.edu.iq/index.php/main/article/view/367.