@article{DE_1975_11_1_a3,
     author = {V. N. Vragov},
     title = {Some boundary value problems for a certain class of equations of mixed type in the three-dimensional case},
     journal = {Differencialʹnye uravneni\^a},
     pages = {27--32},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_1_a3/}
}