@article{DAN_1986_286_6_a4,
     author = {N. S. Nadirashvili},
     title = {Multiplicity of eigenvalues of the {Neumann} problem},
     journal = {Doklady Akademii Nauk},
     pages = {1303--1305},
     publisher = {mathdoc},
     volume = {286},
     number = {6},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1986_286_6_a4/}
}