@article{DE_1989_25_8_a2,
     author = {H. M. Karov},
     title = {An inequality of {Hilbert} type in a system of eigen- and associated functions of a second-order differential operator for odd and even functions},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1307--1312},
     publisher = {mathdoc},
     volume = {25},
     number = {8},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_8_a2/}
}