@article{DAN_1971_199_4_a7,
     author = {A. A. Karatsuba},
     title = {On a certain arithmetic sum},
     journal = {Doklady Akademii Nauk},
     pages = {770--772},
     publisher = {mathdoc},
     volume = {199},
     number = {4},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_199_4_a7/}
}