@article{PMIHES_2009__109__1_0,
     author = {Arnaud, M.-C.},
     title = {Three results on the regularity of the curves that are invariant by an exact symplectic twist map},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {1--17},
     publisher = {Springer-Verlag},
     volume = {109},
     year = {2009},
     doi = {10.1007/s10240-009-0017-8},
     mrnumber = {2511585},
     zbl = {1177.53070},
     language = {en},
     url = {http://www.numdam.org/articles/10.1007/s10240-009-0017-8/}
}