@article{IM2_2018_82_2_a3,
     author = {K. B. Sabitov and R. M. Safina},
     title = {The first boundary-value problem for an equation of mixed type with a~singular coefficient},
     journal = {Izvestiya. Mathematics },
     pages = {318--350},
     publisher = {mathdoc},
     volume = {82},
     number = {2},
     year = {2018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2018_82_2_a3/}
}