@article{IVM_2013_10_a3,
     author = {E. A. Sozontova},
     title = {Characteristic problems with normal derivatives for hyperbolic systems},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {43--54},
     publisher = {mathdoc},
     number = {10},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2013_10_a3/}
}