@article{MMO_1966_15_a8,
     author = {M. V. Fedoryuk},
     title = {Asymptotic methods in the theory of one-dimensional singular differential operators},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {296--345},
     publisher = {mathdoc},
     volume = {15},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1966_15_a8/}
}