@article{MZM_1968_4_6_a9,
     author = {V. A. Bolgov},
     title = {The summation of orthogonal series by linear methods},
     journal = {Matemati\v{c}eskie zametki},
     pages = {697--705},
     publisher = {mathdoc},
     volume = {4},
     number = {6},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1968_4_6_a9/}
}