@article{TRSPY_1981_157_a5,
     author = {B. S. Kashin and S. V. Konyagin},
     title = {Systems of vectors in {Hilbert} space},
     journal = {Informatics and Automation},
     pages = {64--67},
     publisher = {mathdoc},
     volume = {157},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1981_157_a5/}
}