@article{RM_1991_46_1_a0,
     author = {Yu. S. Ilyashenko and S. Yu. Yakovenko},
     title = {Finitely-smooth normal forms of local families of diffeomorphisms and vector fields},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {1--43},
     publisher = {mathdoc},
     volume = {46},
     number = {1},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1991_46_1_a0/}
}