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@article{IVM_1973_9_a13, author = {V. A. Shtraus}, title = {$G$-orthonormal systems and bases in {Hilbert} space}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {108--117}, publisher = {mathdoc}, number = {9}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1973_9_a13/} }
V. A. Shtraus. $G$-orthonormal systems and bases in Hilbert space. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 9 (1973), pp. 108-117. http://geodesic.mathdoc.fr/item/IVM_1973_9_a13/