Nagy, Zoltán, and Tekla Sebestyen Szep. “Losers of the Falling Oil Prices: Changes in Oil Vulnerability in the Oil Exporting Countries”. International Journal of Energy Economics and Policy, vol. 6, no. 4, Oct. 2016, pp. 738-52, https://econjournals.com/index.php/ijeep/article/view/2706.