SosnitskiiS. P. “On One Atypical Scheme of Application of the Second Lyapunov Method”. Ukrains’kyi Matematychnyi Zhurnal 61, no. 11 (November 25, 2009): 1557-1563. Accessed November 23, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3121.