@article{DE_1993_29_1_a12,
     author = {Ya. N. Mamedov},
     title = {On the eigenvalue problem for equations of mixed type},
     journal = {Differencialʹnye uravneni\^a},
     pages = {95--103},
     publisher = {mathdoc},
     volume = {29},
     number = {1},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_1_a12/}
}