@article{DE_1988_24_1_a13,
     author = {A. S. Makin},
     title = {Some properties of the eigen- and associated functions of an elliptic second-order operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {116--123},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_1_a13/}
}