@article{GMJ_1998__5_2_47995,
     author = {Kharibegashvili, S.},
     title = {On some multidimensional versions of a characteristic problem for second-order degenerating hyperbolic equations.},
     journal = {Georgian mathematical journal},
     pages = {139--156},
     year = {1998},
     volume = {5},
     number = {2},
     zbl = {0898.35062},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/GMJ_1998__5_2_47995/}
}