@article{FAA_1967_1_1_a7,
     author = {A. G. Kostyuchenko and B. M. Levitan},
     title = {Asymptotic behavior of the eigenvalues of the {Sturm--Liouville} operator problem},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {86--96},
     publisher = {mathdoc},
     volume = {1},
     number = {1},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1967_1_1_a7/}
}