@article{DAN_1969_188_5_a5,
     author = {M. M. Zainulabidov},
     title = {A certain boundary value problem for a model equation of mixed type with two perpendicular lines of degeneracy},
     journal = {Doklady Akademii Nauk},
     pages = {986--989},
     publisher = {mathdoc},
     volume = {188},
     number = {5},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_188_5_a5/}
}