TY  - JOUR
AU  - I. A. Kipriyanov
TI  - Degenerate differential operators of principal type
JO  - Doklady Akademii Nauk
PY  - 1973
SP  - 1247
EP  - 1250
VL  - 213
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1973_213_6_a4/
LA  - ru
ID  - DAN_1973_213_6_a4
ER  -