Lawal, A. I., Babajide, A. A., Nwanji, T. I., & Eluyela, D. (2018). Are Oil Prices Mean Reverting? Evidence from Unit Root Tests with Sharp and Smooth Breaks. International Journal of Energy Economics and Policy, 8(6), 292–298. Retrieved from https://mail.econjournals.com/index.php/ijeep/article/view/6980