Boichuk О. A., and V. P. Zhuravliov. “Boundary-Value Problems With Control for Operator Equations in Banach Spaces”. Ukrains’kyi Matematychnyi Zhurnal 73, no. 5 (May 24, 2021): 602 - 616. Accessed March 29, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/6537.