@article{IM2_1971_5_2_a9,
     author = {M. Sh. Birman},
     title = {Scattering problems for differential operators with perturbation of the space},
     journal = {Izvestiya. Mathematics },
     pages = {459--474},
     publisher = {mathdoc},
     volume = {5},
     number = {2},
     year = {1971},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1971_5_2_a9/}
}