TY  - JOUR
AU  - A. M. Popov
TI  - Helmholtz potentiality conditions for systems of difference-differential equations
JO  - Matematičeskie zametki
PY  - 1998
SP  - 437
EP  - 442
VL  - 64
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1998_64_3_a12/
LA  - ru
ID  - MZM_1998_64_3_a12
ER  -