@article{DOCMA_2004__9__a25,
     author = {Frank, Rupert L. and Shterenberg, Roman G.},
     title = {On the scattering theory of the {Laplacian} with a periodic boundary condition. {II.} {Additional} channels of scattering},
     journal = {Documenta mathematica},
     pages = {57--77},
     publisher = {mathdoc},
     volume = {9},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DOCMA_2004__9__a25/}
}