V. F. Babenko and A. A. Ligun, “Some Bernstein-type inequalities for trigonometric polynomials”, Ukr. Mat. Zhurn., vol. 45, no. 3, pp. 428–430, Mar. 1993, Accessed: Feb. 17, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5825