Dzyadyk, V. K., and I. A. Shevchuk. 1997. “Remark on the Lebesgue Constant in the Rogosinski Kernel”. Ukrains’kyi Matematychnyi Zhurnal 49 (7), 1002–1004. https://umj.imath.kiev.ua/index.php/umj/article/view/5093.