@article{DE_1981_17_9_a8,
     author = {A. S. Pechentsov},
     title = {Asymptotic expansion of solutions of linear differential equations containing a parameter},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1611--1620},
     publisher = {mathdoc},
     volume = {17},
     number = {9},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_9_a8/}
}