@article{DE_1988_24_1_a20,
     author = {M. M. Zainulabidov},
     title = {The {Tricomi} problem when the line of change of type of the equation is closed},
     journal = {Differencialʹnye uravneni\^a},
     pages = {177--178},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_1_a20/}
}