Akhter, Muhammad Fahim, et al. “Study of Coronal Index Time Series Solar Activity Data in the Perspective of Probability Distribution : Coronal Index Time Series Solar Activity Data and Probability Distribution”. Proceedings of the Pakistan Academy of Sciences: A. Physical and Computational Sciences, vol. 55, no. 1, Apr. 2021, pp. 27-33, http://ppaspk.org/index.php/PPAS-A/article/view/198.