ZERNOV, A. E. Qualitative Analysis of an Implicit Singular Cauchy Problem. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 53, n. 3, p. 302–310, 2001. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4253. Acesso em: 11 apr. 2025.