@article{AA_1991_3_2_a3,
     author = {V. A. Kozlov and V. G. Maz'ya},
     title = {On the spectrum of an operator pencil generated by the {Neumann} problem in a~cone},
     journal = {Algebra i analiz},
     pages = {111--131},
     publisher = {mathdoc},
     volume = {3},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1991_3_2_a3/}
}