TY  - JOUR
AU  - L. Z. Fishman
TI  - On the preservation of the properties of differential equations
JO  - Doklady Akademii Nauk
PY  - 1996
SP  - 594
EP  - 596
VL  - 346
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1996_346_5_a3/
LA  - ru
ID  - DAN_1996_346_5_a3
ER  -