عبود سهيل نجم, and خورشيد ايناس صلاح. “Comparison Between the Methods of Ridge Regression and Liu Type to Estimate the Parameters of the Negative Binomial Regression Model Under Multicollinearity Problem by Using Simulation”. Journal of Economics and Administrative Sciences 24, no. 109 (December 1, 2018): 515. Accessed April 26, 2025. https://jeasiq.uobaghdad.edu.iq/index.php/JEASIQ/article/view/1564.