Fonda, A. and Garrione, M. (2013) “Generalized Sturm-Liouville boundary conditions for first order differential systems in the plane”, Topological Methods in Nonlinear Analysis, 42(2), pp. 293–325. Available at: https://apcz.umk.pl/TMNA/article/view/TMNA.2013.038 (Accessed: 29 March 2024).