MartynyukD. I. “Integration of Linear Differential Equations With a Devicating Argument by Means of Series ”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 5 (August 31, 1966): 105-111. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8447.