[1]
B. R. Draganov, “An Improved Jackson Inequality for the Best Trigonometric Approximation”, Ukr. Mat. Zhurn., vol. 65, no. 9, pp. 1219–1226, Sep. 2013, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2502