@article{DAN_1989_304_2_a1,
     author = {Yu. A. Dubinskii},
     title = {The necessity of {Kovalevskaya} conditions, and their},
     journal = {Doklady Akademii Nauk},
     pages = {268--271},
     publisher = {mathdoc},
     volume = {304},
     number = {2},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_304_2_a1/}
}