@article{DE_1977_13_1_a9,
     author = {G. D. Karatoprakliev},
     title = {On the theory of boundary value problems for mixed type equations in multidimensional domains. {I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {64--75},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_1_a9/}
}