Vovkodav N. G., and Shlepakov L. N. “On the Optimal Coefficient of Efficiency of a Semi-Markov System in the Scheme of Phase Lumping”. Ukrains’kyi Matematychnyi Zhurnal 56, no. 3 (March 25, 2004): 339-345. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3757.