Bahmanshir, R. D., A. A. N. Meidani, M. K. Mashhadi, and N. Salehnia. “Reversibility Test of Oil Demand Function of OECD Countries Importing Oil from Iran With an Emphasis on Technological and Environmental Considerations: Symmetric and Asymmetric Models”. International Journal of Energy Economics and Policy, vol. 8, no. 2, Mar. 2018, pp. 132-9, https://www.econjournals.com/index.php/ijeep/article/view/6116.