@article{FAA_2013_47_3_a5,
     author = {A. Sowa},
     title = {The {Dirichlet} {Ring} and {Unconditional} {Bases} in $L_2[0,2\pi]$},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {75--81},
     publisher = {mathdoc},
     volume = {47},
     number = {3},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_2013_47_3_a5/}
}