Makhmudov A. P., & Le Dyk Kiem. (1992). On the approximation by the poynomials of S. M. Bershtein type of the Hursa problem for nonlinear equation of hyperbolic type. Ukrains’kyi Matematychnyi Zhurnal, 44(8), 1116-1123. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/8044