@article{ZVMMF_2013_53_5_a8,
     author = {V. A. Malakhov and A. V. Nazarov and A. S. Raevskii and S. B. Raevskii},
     title = {Multiplicity of eigenvalues in certain boundary value problems for the {Helmholtz} equation},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {783--791},
     year = {2013},
     volume = {53},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_2013_53_5_a8/}
}