SemenyukV. B. (1994) “Approximation of differentiable functions by polynomial splines in domains with external peaks”, Ukrains’kyi Matematychnyi Zhurnal, 46(9), pp. 1224–1233. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5639 (Accessed: 27July2024).