Kaplun, Y.I. and Samoilenko, V.G. (2003) “On Extendability of Solutions of Differential Equations to a Singular Set”, Ukrains’kyi Matematychnyi Zhurnal, 55(3), pp. 373–378. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/3911 (Accessed: 17 February 2026).