Horbatenko, Ya. V. “Kostin-Type Criterion for Abstract Linear Differential Equations of Arbitrary Order in Banach Spaces”. Ukrains’kyi Matematychnyi Zhurnal 62, no. 6 (June 25, 2010): 860 -. Accessed May 3, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2918.