Yezhov, I. I., and V. F. Kadankov. 1993. “Limit Functionals for a Semicontinuous Difference of Renewal Processes With Discrete Time”. Ukrains’kyi Matematychnyi Zhurnal 45 (12): 1710–1712. https://umj.imath.kiev.ua/index.php/umj/article/view/5981.