Statkevych, V. M. “Systems of Essentially Infinite-Dimensional Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 63, no. 9 (September 25, 2011): 1257-1262. Accessed April 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2802.