@article{DAN_1969_185_6_a0,
     author = {M. A. Aleksidze and N. M. Arveladze and N. L. Lekishvili and K. V. Pertaya},
     title = {The expansion of functions in approximately orthonormal systems},
     journal = {Doklady Akademii Nauk},
     pages = {1207--1210},
     publisher = {mathdoc},
     volume = {185},
     number = {6},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_185_6_a0/}
}