SotnichenkoN. A. “Asymptotics of Solutions of à System of Differential Equations With ‘turning points’”. Ukrains’kyi Matematychnyi Zhurnal 48, no. 6 (June 25, 1996): 861-862. Accessed September 1, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5288.