@article{FAA_1990_24_2_a9,
     author = {I. U. Bronshtein and A. Ya. Kopanskii},
     title = {Finitely smooth polynomial normal forms of $C^\infty$-diffeomorphisms in the neighborhood of a fixed point},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {79--80},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1990_24_2_a9/}
}