@article{DE_1971_7_10_a7,
     author = {V. N. Laptinskii},
     title = {A certain matrix method in the theory of oscillations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1819--1824},
     publisher = {mathdoc},
     volume = {7},
     number = {10},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_10_a7/}
}