Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1976_230_2_a0, author = {A. D. Bruno}, title = {Normal form and averaging methods}, journal = {Doklady Akademii Nauk}, pages = {257--260}, publisher = {mathdoc}, volume = {230}, number = {2}, year = {1976}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1976_230_2_a0/} }
A. D. Bruno. Normal form and averaging methods. Doklady Akademii Nauk, Tome 230 (1976) no. 2, pp. 257-260. http://geodesic.mathdoc.fr/item/DAN_1976_230_2_a0/