Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1998_64_3_a12, author = {A. M. Popov}, title = {Helmholtz potentiality conditions for systems of difference-differential equations}, journal = {Matemati\v{c}eskie zametki}, pages = {437--442}, publisher = {mathdoc}, volume = {64}, number = {3}, year = {1998}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1998_64_3_a12/} }
A. M. Popov. Helmholtz potentiality conditions for systems of difference-differential equations. Matematičeskie zametki, Tome 64 (1998) no. 3, pp. 437-442. http://geodesic.mathdoc.fr/item/MZM_1998_64_3_a12/