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@article{MZM_1969_6_6_a9, author = {A. M. Olevskii}, title = {On the extension of a~sequence of functions to a~complete orthonormal system}, journal = {Matemati\v{c}eskie zametki}, pages = {737--747}, publisher = {mathdoc}, volume = {6}, number = {6}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1969_6_6_a9/} }
A. M. Olevskii. On the extension of a~sequence of functions to a~complete orthonormal system. Matematičeskie zametki, Tome 6 (1969) no. 6, pp. 737-747. http://geodesic.mathdoc.fr/item/MZM_1969_6_6_a9/