KomlevaT. A., PlotnikovA. V., and PlotnikovaL. I. “One Multivalued Discrete System and Its Properties”. Ukrains’kyi Matematychnyi Zhurnal 70, no. 11 (November 25, 2018): 1519-1524. Accessed December 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/1655.