Yezhov, I. I., and V. F. Kadankov. “Boundary Functionals for the Difference of Nonordinary Renewal Processes With Discrete Time”. Ukrains’kyi Matematychnyi Zhurnal 52, no. 10 (October 25, 2000): 1345–1356. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4541.