TY  - JOUR
AU  - A. H. Hovhannisyan
TI  - Structure of hyperbolic equations with variable coefficients that
JO  - Doklady Akademii Nauk
PY  - 1990
SP  - 1072
EP  - 1075
VL  - 314
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1990_314_5_a11/
LA  - ru
ID  - DAN_1990_314_5_a11
ER  -