@article{ASNSP_1987_4_14_1_79_0,
     author = {Dieckerhoff, R. and Zehnder, E.},
     title = {Boundedness of solutions via the twist-theorem},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {79--95},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 14},
     number = {1},
     year = {1987},
     mrnumber = {937537},
     zbl = {0656.34027},
     language = {en},
     url = {http://archive.numdam.org/item/ASNSP_1987_4_14_1_79_0/}
}