TY  - JOUR
AU  - V. V. Lychagin
TI  - Local classification of first-order nonlinear partial differential equations
JO  - Doklady Akademii Nauk
PY  - 1973
SP  - 525
EP  - 528
VL  - 210
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1973_210_3_a4/
LA  - ru
ID  - DAN_1973_210_3_a4
ER  -