BONDAR, A. V. On differentiability of open mappings. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 12, p. 1587–1600, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4778. Acesso em: 7 apr. 2025.