@article{ASNSP_1990_4_17_1_35_0,
     author = {Long, Yiming},
     title = {Periodic solutions of perturbed superquadratic hamiltonian systems},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {35--77},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 17},
     number = {1},
     year = {1990},
     mrnumber = {1074626},
     zbl = {0724.34052},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1990_4_17_1_35_0/}
}