@article{IVM_1993_2_a6,
     author = {I. S. Krasil'shchik},
     title = {Some new cohomological invariants of nonlinear differential {equations.~II}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {54--68},
     publisher = {mathdoc},
     number = {2},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1993_2_a6/}
}