@article{DAN_1988_298_5_a3,
     author = {A. Dzhuraev},
     title = {Degenerate elliptic and first-order mixed-type systems in a plane},
     journal = {Doklady Akademii Nauk},
     pages = {1047--1051},
     publisher = {mathdoc},
     volume = {298},
     number = {5},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_298_5_a3/}
}