@article{DAN_1973_208_3_a6,
     author = {G. D. Karatoprakliev},
     title = {On an equation of mixed type in multidimensional domains},
     journal = {Doklady Akademii Nauk},
     pages = {528--530},
     publisher = {mathdoc},
     volume = {208},
     number = {3},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_208_3_a6/}
}