@article{SM_1991_70_2_a7,
     author = {M. G. Grigoryan},
     title = {On convergence of {Fourier} series in complete orthonormal systems in the $L^1$-metric and almost everywhere},
     journal = {Sbornik. Mathematics},
     pages = {445--466},
     publisher = {mathdoc},
     volume = {70},
     number = {2},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1991_70_2_a7/}
}