TY  - JOUR
AU  - V. V. Grushin
TI  - On~a~class of hypoelliptic operators
JO  - Sbornik. Mathematics
PY  - 1970
SP  - 458
EP  - 476
VL  - 12
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1970_12_3_a7/
LA  - en
ID  - SM_1970_12_3_a7
ER  -