@article{DAN_1993_328_5_a3,
     author = {L. V. Zilbergleit and V. V. Lychagin},
     title = {Spencer cohomology of invariant systems of differential equations},
     journal = {Doklady Akademii Nauk},
     pages = {544--546},
     publisher = {mathdoc},
     volume = {328},
     number = {5},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1993_328_5_a3/}
}