@article{DE_1974_10_11_a10,
     author = {Ya. T. Sultanaev},
     title = {Asymptotic behavior of the discrete spectrum of one-dimensional singular differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2010--2020},
     publisher = {mathdoc},
     volume = {10},
     number = {11},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_11_a10/}
}