TY  - JOUR
AU  - A. A. Iosif'yan
TI  - Characteristic problems with a principal part that contains mixed derivatives
JO  - Differencialʹnye uravneniâ
PY  - 1976
SP  - 309
EP  - 324
VL  - 12
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_1976_12_2_a14/
LA  - ru
ID  - DE_1976_12_2_a14
ER  -