Radchenko, S., V. Samoilenko, and P. Samusenko. “Asymptotic Solutions of Singularly Perturbed Linear Differential-Algebraic Equations With Periodic Coefficients”. Matematychni Studii 59, no. 2 (June 23, 2023): 187-200. Accessed November 23, 2024. http://matstud.org.ua/ojs/index.php/matstud/article/view/400.