@article{ZVMMF_1980_20_3_a5,
     author = {V. V. Ditkin},
     title = {Approximate calculation of eigenvalues with a parameter in the boundary conditions},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {597--604},
     year = {1980},
     volume = {20},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1980_20_3_a5/}
}