Vakarchuk S, Vakarchuk M. Approximation in the mean of the classes of functions in the space $L_2[(0,1);x]$ by the Fourier–Bessel sums and estimates of the values of their $n$-widths. Ukr. Mat. Zhurn. [Internet]. 2024 Feb. 28 [cited 2025 Dec. 5];76(2):198-223. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/7763