TY  - JOUR
AU  - A. V. Bitsadze
TI  - On the question of formulating the characteristic problem for second order hyperbolic systems
JO  - Doklady Akademii Nauk
PY  - 1975
SP  - 1289
EP  - 1292
VL  - 223
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1975_223_6_a0/
LA  - ru
ID  - DAN_1975_223_6_a0
ER  -