@article{00645168, title = {On convergence subsystems of orthonormal systems.}, journal = {Georgian Mathematical Journal}, volume = {1}, year = {1994}, pages = {235-242}, doi = {10.1007/BF02254672}, zbl = {0811.42009}, language = {en}, url = {http://dml.mathdoc.fr/item/00645168} }
Bareladze, G. On convergence subsystems of orthonormal systems.. Georgian Mathematical Journal, Tome 1 (1994) pp. 235-242. doi : 10.1007/BF02254672. http://gdmltest.u-ga.fr/item/00645168/