Abdullayev, F., A. Serdyuk, and A. Shidlich. “Widths of Functional Classes Defined by Majorants of Generalized Moduli of Smoothness in the Spaces ${\mathcal S}^{p}$”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 73, no. 6, June 2021, pp. 723 -7, doi:10.37863/umzh.v73i6.6432.