@article{DE_1984_20_11_a27,
     author = {K. S. Matviychuk},
     title = {On a comparison method for differential equations close to hyperbolic ones},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2009--2011},
     year = {1984},
     volume = {20},
     number = {11},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_11_a27/}
}