@article{KUKZ_1975_12_12_a15,
     author = {Yu. M. Krikunov},
     title = {A particular case of the equation $K(y)u_{xx}+\operatorname{sgn}(xy)K(x)u_{yy}=0$},
     journal = {Trudy seminara po kraevym zada\v{c}am},
     pages = {126--133},
     publisher = {mathdoc},
     volume = {12},
     number = {12},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUKZ_1975_12_12_a15/}
}