Jiménez-Preciado, A. L., S. Cruz-Aké, and F. Venegas-Martínez. “Persistency of Price Patterns in the International Oil Industry, 2001-2016”. International Journal of Energy Economics and Policy, vol. 7, no. 1, Jan. 2017, pp. 9-18, https://www.econjournals.com/index.php/ijeep/article/view/3306.