@article{AIHPA_1985__42_1_109_0,
     author = {Ruelle, David},
     title = {Rotation numbers for diffeomorphisms and flows},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {109--115},
     publisher = {Gauthier-Villars},
     volume = {42},
     number = {1},
     year = {1985},
     mrnumber = {794367},
     zbl = {0556.58026},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1985__42_1_109_0/}
}