M. A. El-Damcese, Abdelfattah Mustafa, B. S. El-Desouky, and M. E. Mustafa. “The Kumaraswamy Flexible Weibull Extension”. International Journal of Mathematics And Its Applications, vol. 4, no. 1 - A, Jan. 2016, pp. 1-14, http://ijmaa.in/index.php/ijmaa/article/view/540.