Fattah, A. M. A., and E. A. Rady. “On Sampling Distribution of Improved Estimators for Coefficients in Seemingly Unrelated Regression SUR Models”. International Journal of Sciences: Basic and Applied Research (IJSBAR) 26, no. 2 (April 14, 2016): 94–103. Accessed July 23, 2024. https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/3889.