Corona, Dario, Roberto Giambò, Fabio Giannoni, and Paolo Piccione. “On the Relative Category in the Brake Orbits Problem”. Topological Methods in Nonlinear Analysis 61, no. 1 (March 4, 2023): 199–215. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/42926.