Shubita, Rawan F., and Taleb Awad Warrad. “The Effects of International Trade Openness on Government Revenue: Empirical Evidence from Middle East and North African Region Countries”. International Journal of Economics and Financial Issues, vol. 8, no. 1, Jan. 2018, pp. 153-60, https://mail.econjournals.com/index.php/ijefi/article/view/5980.