@article{SM_1999_190_1_a1,
     author = {M. S. Agranovich and R. Mennicken},
     title = {Spectral boundary value problems for {the~Helmholtz} equation with spectral parameter in~boundary conditions on a~non-smooth surface},
     journal = {Sbornik. Mathematics},
     pages = {29--69},
     publisher = {mathdoc},
     volume = {190},
     number = {1},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1999_190_1_a1/}
}