ShydlichA. L. 2008. “Saturation of the Linear Methods of Summation of Fourier Series in the Spaces <i>S^p</i><sub>φ</Sub&gt;”. Ukrains’kyi Matematychnyi Zhurnal 60 (6), 815 -. https://umj.imath.kiev.ua/index.php/umj/article/view/3198.