CAPONETTI, Diana, TROMBETTA, Alessandro and TROMBETTA, Giulio. Proper $k$-ball-contractive mappings in $C_b^m[0, + \infty)$. Topological Methods in Nonlinear Analysis. Online. 13 December 2021. Vol. 58, no. 2, pp. 609 - 639. [Accessed 3 July 2024]. DOI 10.12775/TMNA.2021.017.