Nair, N. Unnikrishnan, P. G. Sankaran, and Nidhi P. Ramesh. “Discrete Distributions With Bathtub-Shaped Hazard Rates”. South African Statistical Journal 51, no. 1 (March 31, 2017): 81–102. Accessed April 3, 2026. https://www.journals.ac.za/index.php/sasj/article/view/5225.