@article{DAN_1981_256_3_a11,
     author = {A. S. Silbergleit and Ju. I. Kopilevich},
     title = {On properties of waves associated with quadratic operator pencils},
     journal = {Doklady Akademii Nauk},
     pages = {565--570},
     publisher = {mathdoc},
     volume = {256},
     number = {3},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1981_256_3_a11/}
}