Kmit, I. Ya., L. Recke, and V. I. Tkachenko. “Robustness of Exponential Dichotomies of Boundary-Value Problems for General First-Order Hyperbolic Systems”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 2 (February 25, 2013): 236-251. Accessed January 28, 2023. https://umj.imath.kiev.ua/index.php/umj/article/view/2415.