Hendrawaty, E., R. Azhar, F. S. D. Kesumah, S. I. O. Sembiring, and M. Metalia. “Modelling and Forecasting Crude Oil Prices During COVID-19 Pandemic”. International Journal of Energy Economics and Policy, vol. 11, no. 2, Feb. 2021, pp. 149-54, https://econjournals.com/index.php/ijeep/article/view/10578.