@article{IM2_2017_81_1_a6,
     author = {V. Sh. Tsagareishvili},
     title = {On {Fourier} coefficients of functions with respect to general orthonormal systems},
     journal = {Izvestiya. Mathematics},
     pages = {179--198},
     year = {2017},
     volume = {81},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2017_81_1_a6/}
}