U. Z. Hrabova, I. V. Kalchuk, and T. A. Stepanyuk, “Approximation of functions from the classes $W_{β}^r H^{α }$ by Weierstrass integrals”, Ukr. Mat. Zhurn., vol. 69, no. 4, pp. 510–519, Apr. 2017, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1712