@article{AIHPC_1992__9_2_187_0,
     author = {Ambrosetti, A. and Coti-Zelati, V.},
     title = {Closed orbits of fixed energy for a class of {N-body} problems},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {187--200},
     publisher = {Gauthier-Villars},
     volume = {9},
     number = {2},
     year = {1992},
     mrnumber = {1160848},
     zbl = {0757.70007},
     language = {en},
     url = {http://www.numdam.org/item/AIHPC_1992__9_2_187_0/}
}