@article{DE_1994_30_12_a19,
     author = {V. V. Trefilov},
     title = {On a system of basis functions for linear differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2186--2187},
     year = {1994},
     volume = {30},
     number = {12},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1994_30_12_a19/}
}