TY  - JOUR
AU  - V. E. Balabaev
TI  - The Ellipticity Problem for Systems of First-Order Partial Differential Equations
JO  - Differencialʹnye uravneniâ
PY  - 2002
SP  - 411
EP  - 413
VL  - 38
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_2002_38_3_a17/
LA  - ru
ID  - DE_2002_38_3_a17
ER  -