@article{DAN_1957_116_5_a8,
     author = {A. K. Pokalo},
     title = {On the summation of functions of the $B^{(r)}$ classes},
     journal = {Doklady Akademii Nauk},
     pages = {750--753},
     publisher = {mathdoc},
     volume = {116},
     number = {5},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_116_5_a8/}
}