Rukasov V. I. “Approximation of the Functions Preset on the Real Axis by the Valle Pussen Operators ”. Ukrains’kyi Matematychnyi Zhurnal 44, no. 5 (May 26, 1992): 682-691. Accessed October 6, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/7965.