TY  - JOUR
AU  - A. Yu. Veretennikov
TI  - Conditions for hypo-ellipticity and estimates for the rate of
JO  - Doklady Akademii Nauk
PY  - 1989
SP  - 524
EP  - 526
VL  - 307
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1989_307_3_a1/
LA  - ru
ID  - DAN_1989_307_3_a1
ER  -