@article{DE_1966_2_7_a3,
     author = {N. A. Izobov},
     title = {Stability with respect to the first approximation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {898--907},
     year = {1966},
     volume = {2},
     number = {7},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1966_2_7_a3/}
}