@article{ZVMMF_1991_31_6_a4,
     author = {A. A. Abramov},
     title = {A~method of finding the eigenvalues and eigenfunctions of a~self-conjugate differential problem},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {819--831},
     publisher = {mathdoc},
     volume = {31},
     number = {6},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1991_31_6_a4/}
}