Radzievskii, G. V. “Asymptotics of the Fundamental System of Solutions of a Linear Functional-Differential Equation With Respect to a Parameter”. Ukrains’kyi Matematychnyi Zhurnal 47, no. 6 (June 25, 1995): 811–836. Accessed June 2, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5475.