@article{DAN_1990_314_1_a16,
     author = {N. D. Kopachevskii},
     title = {Inversion of {Lagrange's} theorem on the stability of small},
     journal = {Doklady Akademii Nauk},
     pages = {71--73},
     year = {1990},
     volume = {314},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_314_1_a16/}
}