Samoilenko , A. M., and P. F. Samusenko. “Asymptotic Integration of Singularly Perturbed Differential Algebraic Equations With Turning Points. Part I”. Ukrains’kyi Matematychnyi Zhurnal 72, no. 12 (December 24, 2020): 1669-1681. Accessed April 18, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/6261.