GorodetskiiV. G. “Boundedness of Solutions and Asymptotic Properties of Some Systems of Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 46, no. 7 (July 25, 1994): 944–946. Accessed October 6, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5687.