Y. M. Dyukarev, “Nevanlinna–Pick Problem for Stieltjes Matrix Functions”, Ukr. Mat. Zhurn., vol. 56, no. 3, pp. 366–380, Mar. 2004, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3760