Barzanti, Luca, and Corrado Corradi. “A Stable Iterative Algorithm for Evaluation of Upper and Lower Approximations to Ultimate Ruin Probabilities”. Statistica 63, no. 1 (January 1, 2003): 13–21. Accessed October 27, 2021. https://rivista-statistica.unibo.it/article/view/1232.