@article{DE_1967_3_5_a8,
     author = {N. A. Izobov},
     title = {Weakly irregular system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {787--795},
     publisher = {mathdoc},
     volume = {3},
     number = {5},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1967_3_5_a8/}
}