@article{IVM_1990_5_a1,
     author = {V. F. Gaposhkin},
     title = {Series of block-orthogonal and block-independent systems},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {12--18},
     year = {1990},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1990_5_a1/}
}