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@article{IVM_1992_10_a12, author = {M. G. Grigoryan}, title = {On certain properties of orthogonal systems}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {80--82}, publisher = {mathdoc}, number = {10}, year = {1992}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1992_10_a12/} }
M. G. Grigoryan. On certain properties of orthogonal systems. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 10 (1992), pp. 80-82. http://geodesic.mathdoc.fr/item/IVM_1992_10_a12/