Gurgul, Henryk, and Robert Syrek. “Mutual Information Between the Main Foreign Subindices: The Application of Copula Entropy Around WHO’s Declaration Date at the Time of the COVID-19 Pandemic”. International Entrepreneurship Review 10, no. 2 (June 30, 2024): 7–24. Accessed December 21, 2024. https://ier.uek.krakow.pl/index.php/pm/article/view/2208.