@article{DE_1992_28_1_a2,
     author = {V. D. Budaev},
     title = {Criteria for the {Bessel} property and the {Riesz} basis property of systems of root functions of differential operators. {II}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {23--33},
     publisher = {mathdoc},
     volume = {28},
     number = {1},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1992_28_1_a2/}
}