Guesmi, Khaled, Frederic Teulon, and Zied Ftiti. “Sudden Changes In Volatility In European Stock Markets”. Journal of Applied Business Research (JABR) 30, no. 6 (October 21, 2014): 1567–1576. Accessed January 30, 2023. https://clutejournals.com/index.php/JABR/article/view/8872.