Shydlich, A. L. “Saturation of the Linear Methods of Summation of Fourier Series in the Spaces S Pφ”. Ukrains’kyi Matematychnyi Zhurnal 60, no. 6 (June 25, 2008): 815 – 828. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3198.