TY  - JOUR
AU  - Le Khyu Zien
AU  - V. I. Shevchenko
TI  - Homotopy classification of systems in the plane that are elliptic in the sense of Douglis and Nirenberg
JO  - Doklady Akademii Nauk
PY  - 1979
SP  - 824
EP  - 827
VL  - 244
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1979_244_4_a7/
LA  - ru
ID  - DAN_1979_244_4_a7
ER  -