Zelinskii, Yu. B., B. A. Klishchuk, and M. V. Tkachuk. 2014. “Theorems on Inclusion for Multivalued Mappings”. Ukrains’kyi Matematychnyi Zhurnal 66 (7), 1003–1005. https://umj.imath.kiev.ua/index.php/umj/article/view/2194.