@article{DE_1973_9_5_a0,
     author = {A. F. Andreev},
     title = {On the distinguishing problem for $N_2$ in $R^n$},
     journal = {Differencialʹnye uravneni\^a},
     pages = {791--796},
     publisher = {mathdoc},
     volume = {9},
     number = {5},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_5_a0/}
}