OstrovskayaО. V. “Approximation of Continuous Functions Defined on the Real Axis by Generalized Zygmund Operators”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 11 (November 25, 1999): 1505–1512. Accessed May 18, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4752.