Malovichko , V. A. “On Solvability of Nonlocal Boundary Value Problems for Certain Sets of Evolutionary differential         Equations”. Ukrains’kyi Matematychnyi Zhurnal 43, no. 2 (June 30, 2025): 211–216. Accessed December 7, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/9359.