@article{DE_1971_7_10_a10,
     author = {G. A. Il'yushina},
     title = {The generalized localization principle for spectral expansions connected with the {Beltrami} operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1845--1853},
     publisher = {mathdoc},
     volume = {7},
     number = {10},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_10_a10/}
}