@article{DE_2004_40_1_a7,
     author = {O. M. Dzhokhadze},
     title = {Laplace {Invariants} for {Some} {Classes} of {Linear} {Partial} {Differential} {Equations}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {58--68},
     publisher = {mathdoc},
     volume = {40},
     number = {1},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2004_40_1_a7/}
}