@article{DE_1973_9_1_a21,
     author = {V. P. Didenko},
     title = {Certain boundary value problems for a multi-dimensional equation of mixed type},
     journal = {Differencialʹnye uravneni\^a},
     pages = {172--174},
     year = {1973},
     volume = {9},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_1_a21/}
}