TY  - JOUR
AU  - S. Z. Levendorskii
TI  - On~the symbols of degenerate elliptic differential and hypoelliptic pseudodifferential operators
JO  - Izvestiya. Mathematics 
PY  - 1989
SP  - 543
EP  - 561
VL  - 32
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1989_32_3_a4/
LA  - en
ID  - IM2_1989_32_3_a4
ER  -