@article{IVM_1965_2_a1,
     author = {B. E. Veits},
     title = {Bessel and {Hilbert} systems in {Banach} spaces and questions of stability},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {7--23},
     publisher = {mathdoc},
     number = {2},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1965_2_a1/}
}