Terteryan, A. (1992) “Positive difference operators of any preassigned approximation order for the second derivative”,
Ukrains’kyi Matematychnyi Zhurnal, 44(11), pp. 1590–1597. Available at:
https://umj.imath.kiev.ua/index.php/umj/article/view/8262 (Accessed: 16 April 2025).