@article{DAN_1963_150_1_a4,
     author = {G. Karatoprakliev},
     title = {A modified $\mathrm{T}_1$ problem for the equation $u_{xx}+\operatorname{sign}yn u_{yy}=0$},
     journal = {Doklady Akademii Nauk},
     pages = {23--25},
     publisher = {mathdoc},
     volume = {150},
     number = {1},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_150_1_a4/}
}