@article{DE_1999_35_3_a15,
     author = {V. N. Sushch},
     title = {On some difference analogues of first-order invariant hyperbolic systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {411--417},
     publisher = {mathdoc},
     volume = {35},
     number = {3},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_3_a15/}
}