DekanovS. Y., and MikhalinG. A. “A Generalization of the Rogosinski-Rogosinski Theorem”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 52, no. 2, Feb. 2000, pp. 220-7, https://umj.imath.kiev.ua/index.php/umj/article/view/4410.