TY  - JOUR
AU  - A. D. Bruno
TI  - First approximations of differential equations
JO  - Doklady Akademii Nauk
PY  - 1994
SP  - 413
EP  - 416
VL  - 335
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1994_335_4_a2/
LA  - ru
ID  - DAN_1994_335_4_a2
ER  -