Grebenikov, E. A., and A. V. Chichurin. “Analytic Study of Some Differential Equations Related to Problems of Space Dynamics”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 2 (February 25, 2007): 162–171. Accessed May 26, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3301.