Safaryan, R. G. “$R-D$-Systems and Irzhina’s Branching Processes”. Ukrains’kyi Matematychnyi Zhurnal 43, no. 2 (June 30, 2025): 162–167. Accessed February 17, 2026. https://umj.imath.kiev.ua/index.php/umj/article/view/9351.