Voir la notice de l'article provenant de la source Math-Net.Ru
@article{IVM_1975_5_a8, author = {P. M. Sakhnenko}, title = {Linear summability methods for orthogonal series in $L^2_{[0,1]}$}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {52--66}, publisher = {mathdoc}, number = {5}, year = {1975}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1975_5_a8/} }
P. M. Sakhnenko. Linear summability methods for orthogonal series in $L^2_{[0,1]}$. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 5 (1975), pp. 52-66. http://geodesic.mathdoc.fr/item/IVM_1975_5_a8/