@article{DAN_1975_225_3_a5,
     author = {A. Yu. Levin},
     title = {Some questions on the asymptotics for ordinary linear differential equations},
     journal = {Doklady Akademii Nauk},
     pages = {503--506},
     publisher = {mathdoc},
     volume = {225},
     number = {3},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_225_3_a5/}
}