Safitri, Heni. “Black Swan Event on JCI Value and Sectoral Index for February-April 2020: Effects of Covid-19 in Indonesian Stock Exchange”. Journal of Business and Management Studies 4, no. 1 (January 24, 2022): 57–63. Accessed March 14, 2026. https://al-kindipublishers.org/index.php/jbms/article/view/2782.