Sillah, Bukhari M. S., and Hamad M. Alsheikh. “Income, Price, and Government Expenditure Elasticities of Oil in the Gulf Cooperation Council Countries”. International Journal of Energy Economics and Policy, vol. 2, no. 4, Aug. 2012, pp. 333-41, https://econjournals.com/index.php/ijeep/article/view/223.