Vityuk, A. N. “On the Existence of Solutions for a Differential Inclusion of Fractional Order With Upper-Semicontinuous Right-Hand Side”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 51, no. 11, Nov. 1999, pp. 1562–1565, https://umj.imath.kiev.ua/index.php/umj/article/view/4757.