@article{DE_2002_38_3_a17,
     author = {V. E. Balabaev},
     title = {The {Ellipticity} {Problem} for {Systems} of {First-Order} {Partial} {Differential} {Equations}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {411--413},
     publisher = {mathdoc},
     volume = {38},
     number = {3},
     year = {2002},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2002_38_3_a17/}
}