@article{SM_1997_188_8_a3,
     author = {P. A. Borodin},
     title = {Quasiorthogonal sets and conditions for {a~Banach} space to be {a~Hilbert} space},
     journal = {Sbornik. Mathematics},
     pages = {1171--1182},
     publisher = {mathdoc},
     volume = {188},
     number = {8},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1997_188_8_a3/}
}