Gavrilyuk, V. T. “Asymptotic Estimates of Approximation of Continuous Periodic Functions by the Fourier Sums ”. Ukrains’kyi Matematychnyi Zhurnal 42, no. 6 (June 19, 1990): 747–755. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/8830.