Benabas, Mourad. “Théorie De La Dualité Et Orbites Homoclines De systèmes Gyroscopiques”. Topological Methods in Nonlinear Analysis 8, no. 1 (September 1, 1996): 95–135. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.1996.023.