Maghded Ahmed, Rizgar, and Nida Salim Mala Younis. “Employing the Principal Components in Time Series Models and Selecting the Best Models With Application”. Zanco Journal of Human Sciences 27, no. 2 (April 17, 2023): 434–448. Accessed May 17, 2024. https://zancojournal.su.edu.krd/index.php/JAHS/article/view/552.