@article{ZNSL_1981_110_a1,
     author = {M. Sh. Birman and D. R. Yafaev},
     title = {Asymptotics of the spectrum of the scattering matrix},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {3--29},
     publisher = {mathdoc},
     volume = {110},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1981_110_a1/}
}