@article{DE_1974_10_4_a12,
     author = {Yu. N. Frolov},
     title = {Sequences of linear aggregates that consist of eigenfunctions of a differential operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {676--686},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_4_a12/}
}