@article{MZM_1969_6_4_a10,
     author = {R. S. Davtyan},
     title = {On the order of partial sums of general orthogonal series},
     journal = {Matemati\v{c}eskie zametki},
     pages = {451--462},
     publisher = {mathdoc},
     volume = {6},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1969_6_4_a10/}
}