S. B. Vakarchuk, “Best mean-square approximation of functions defined on the real axis by entire functions of exponential type”, Ukr. Mat. Zhurn., vol. 64, no. 5, pp. 604–615, May 2012, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2601