@article{DAN_1995_344_3_a1,
     author = {A. D. Bruno},
     title = {Methods for computing the normal form},
     journal = {Doklady Akademii Nauk},
     pages = {298--300},
     year = {1995},
     volume = {344},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1995_344_3_a1/}
}