@article{DE_1966_2_4_a4,
     author = {M. V. Fedoryuk},
     title = {The asymptotics of solutions to ordinary linear differential equations of the $n$-th order},
     journal = {Differencialʹnye uravneni\^a},
     pages = {492--507},
     publisher = {mathdoc},
     volume = {2},
     number = {4},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1966_2_4_a4/}
}