@article{DE_1980_16_5_a0,
     author = {V. A. Il'in},
     title = {Necessary and sufficient conditions for spatial decompositions to be bases and to be equiconvergent with a trigonometric {series.~I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {771--794},
     publisher = {mathdoc},
     volume = {16},
     number = {5},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_5_a0/}
}