Gurrib, I., Elsharief, E., & Kamalov, F. (2020). The Effect of Energy Cryptos on Efficient Portfolios of Key Energy Listed Companies in the S&P Composite 1500 Energy Index. International Journal of Energy Economics and Policy, 10(2), 179–193. Retrieved from https://econjournals.com/index.php/ijeep/article/view/8676