TY  - JOUR
AU  - E. V. Radkevich
TI  - Hypoelliptic operators with multiple characteristics
JO  - Sbornik. Mathematics
PY  - 1969
SP  - 181
EP  - 205
VL  - 8
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1969_8_2_a3/
LA  - en
ID  - SM_1969_8_2_a3
ER  -