@article{SM_1982_42_3_a5,
     author = {Yu. S. Barkovskii and V. I. Yudovich},
     title = {Spectral properties of a~class of boundary value problems},
     journal = {Sbornik. Mathematics},
     pages = {387--398},
     publisher = {mathdoc},
     volume = {42},
     number = {3},
     year = {1982},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1982_42_3_a5/}
}