TY  - JOUR
AU  - P. A. Frolov
TI  - Topological structure of normally solvable elliptic operators with constant coefficients in the plane
JO  - Doklady Akademii Nauk
PY  - 1970
SP  - 1238
EP  - 1240
VL  - 191
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1970_191_6_a10/
LA  - ru
ID  - DAN_1970_191_6_a10
ER  -