Vyhovs’ka, I. Yu., Yu. B. Zelinskii, and M. V. Stefanchuk. “Generalized Convex Sets and the problem of Shadow”. Ukrains’kyi Matematychnyi Zhurnal 67, no. 12 (December 25, 2015): 1658-1666. Accessed April 23, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2098.