Doronin, V.G. and Ligun, A.A. (2000) “Exact constants in inequalities of the jackson type for quadrature formulas”, Ukrains’kyi Matematychnyi Zhurnal, 52(1), pp. 46–51. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4395 (Accessed: 5 December 2025).