@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/}
}