@article{DE_1982_18_12_a7,
     author = {M. V. Fedoryuk},
     title = {The {Sturm-Liouville} problem with regular singular {points.~I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2166--2173},
     publisher = {mathdoc},
     volume = {18},
     number = {12},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1982_18_12_a7/}
}