Stanzhitskii, A. N., and A. M. Tkachuk. “On the Relationship Between Properties of Solutions of Difference Equations and the Corresponding Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 7 (July 25, 2005): 989–996. Accessed May 5, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3657.