“Approximation by Step-Hyperbolic Fourier Sums of Classes $\mathbf{MB}^{\omega}_{1,\theta}(\bar{\gamma})$”. Transactions of Institute of Mathematics, the NAS of Ukraine, vol. 11, no. 3, June 2014, pp. 228-40, https://trim.imath.kiev.ua/index.php/trim/article/view/79.