ShchegolevS. A. “On the Solution of a Quasilinear Differential System With Periodic Coefficients”. Ukrains’kyi Matematychnyi Zhurnal 45, no. 8 (August 25, 1993): 1157–1161. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5913.