@article{IVM_2008_11_a3,
     author = {V. I. Zhegalov and A. A. Kungurtsev},
     title = {Characteristic boundary problems for the {Liouville} equation},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {40--47},
     year = {2008},
     number = {11},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2008_11_a3/}
}