@article{AIHPC_1992__9_6_597_0,
     author = {Terracini, Susanna},
     title = {Multiplicity of periodic solution with prescribed energy to singular dynamical systems},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {597--641},
     publisher = {Gauthier-Villars},
     volume = {9},
     number = {6},
     year = {1992},
     mrnumber = {1198306},
     zbl = {0771.34035},
     language = {en},
     url = {http://www.numdam.org/item/AIHPC_1992__9_6_597_0/}
}