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@article{TM_1985_172_a12, author = {B. S. Kashin}, title = {On approximation properties of complete orthonormal systems}, journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova}, pages = {187--191}, publisher = {mathdoc}, volume = {172}, year = {1985}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TM_1985_172_a12/} }
B. S. Kashin. On approximation properties of complete orthonormal systems. Trudy Matematicheskogo Instituta imeni V.A. Steklova, Investigations on the theory of functions of several real variables and approximation of functons, Tome 172 (1985), pp. 187-191. http://geodesic.mathdoc.fr/item/TM_1985_172_a12/