Gurrib, Ikhlaas, Firuz Kamalov, and Elgilani E. Alshareif. “High Frequency Return and Risk Patterns in U.S. Sector ETFs During COVID-19”. International Journal of Energy Economics and Policy 12, no. 5 (September 27, 2022): 441–456. Accessed May 28, 2024. https://www.econjournals.com/index.php/ijeep/article/view/13030.