TY  - JOUR
AU  - V. V. Lychagin
TI  - Nonlinear differential equations and contact geometry
JO  - Doklady Akademii Nauk
PY  - 1978
SP  - 273
EP  - 276
VL  - 238
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1978_238_2_a2/
LA  - ru
ID  - DAN_1978_238_2_a2
ER  -