@article{DAN_1981_259_6_a16,
     author = {A. S. Silbergleit and Ju. I. Kopilevich},
     title = {On the dispersion curves of waveguide systems that are connected with quadratic operator pencils},
     journal = {Doklady Akademii Nauk},
     pages = {1345--1349},
     year = {1981},
     volume = {259},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1981_259_6_a16/}
}