“Solution of the Kolmogorov-Nikol’skii Problem for Three-Harmonic Poisson Integrals on Classes $C^{\psi}_{\beta,\infty}$”. Transactions of Institute of Mathematics, the NAS of Ukraine 11, no. 3 (June 24, 2014): 104–127. Accessed September 9, 2026. https://trim.imath.kiev.ua/index.php/trim/article/view/70.