BENEVIERI, Pierluigi, CALAMAI, Alessandro, FURI, Massimo and PERA, Maria Patrizia. The Brouwer degree associated to classical eigenvalue problems and applications to nonlinear spectral theory. Topological Methods in Nonlinear Analysis. Online. 13 December 2021. Vol. 59, no. 2A, pp. 499 - 523. [Accessed 22 July 2024]. DOI 10.12775/TMNA.2021.006.