@article{DE_1992_28_8_a22,
     author = {V. D. Budaev},
     title = {Some properties of root functions of higher-order ordinary differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1454--1456},
     publisher = {mathdoc},
     volume = {28},
     number = {8},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1992_28_8_a22/}
}