KuzmaN. G. “Asymptotic Splitting of Systems of the Second Order Differential Equations With Slowly Varying and Oscillating Coefficients ”. Ukrains’kyi Matematychnyi Zhurnal 40, no. 5 (August 29, 1988): 642-644. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8816.