@article{MZM_1979_26_6_a5,
     author = {S. S. Shterengas},
     title = {Riesz-summation of fourier series with respect to the eigenfunctions of an abstract operator},
     journal = {Matemati\v{c}eskie zametki},
     pages = {865--873},
     publisher = {mathdoc},
     volume = {26},
     number = {6},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1979_26_6_a5/}
}