BakhtinA. K., DvorakI. Ya., and ZabolotnyiYa. V. 2017. “Estimates of the Product of Inner Radii of five nonoverlapping Domains”. Ukrains’kyi Matematychnyi Zhurnal 69 (2), 261-67. https://umj.imath.kiev.ua/index.php/umj/article/view/1691.