PIASECKI, Łukasz. Retracting ball onto sphere in $BC_0(\mathbb R)$. Topological Methods in Nonlinear Analysis, [S. l.], v. 33, n. 2, p. 307–313, 2009. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2009.020. Acesso em: 22 jul. 2024.