@article{MZM_1975_18_2_a8,
     author = {A. D. Bruno},
     title = {Normal form of real differential equations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {227--241},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1975_18_2_a8/}
}