AL-Shareefi, Emad Farhood. “The Missing Observations in the Time Series of the Dependent Variable and Their Location in the Simple Linear Regression Analysis and Their Effect on Prediction (Applied Study in Textile Factory Dhi Qar(”. Journal of University of Babylon for Humanities 26, no. 7 (July 31, 2018): 570 - 579. Accessed May 30, 2020.