@article{AIHP_1939__9_3_51_0,
     author = {Birkhoff, George D.},
     title = {D\'eformations analytiques et fonctions auto-\'equivalentes},
     journal = {Annales de l'institut Henri Poincar\'e},
     pages = {51--122},
     publisher = {INSTITUT HENRI POINCAR\'E ET GAUTHIER-VILLARS},
     volume = {9},
     number = {3},
     year = {1939},
     zbl = {0063.00405},
     language = {fr},
     url = {http://www.numdam.org/item/AIHP_1939__9_3_51_0/}
}