@article{ZNSL_2001_275_a3,
     author = {M. I. Belishev and S. A. Ivanov},
     title = {A local uniqueness in the dynamical inverse problem for the two--velosity system},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {41--54},
     publisher = {mathdoc},
     volume = {275},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2001_275_a3/}
}