@article{DE_1997_33_1_a10,
     author = {V. V. Filippov},
     title = {On a theorem of {Aronszajn}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {75--79},
     publisher = {mathdoc},
     volume = {33},
     number = {1},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1997_33_1_a10/}
}