@article{DAN_1964_158_5_a8,
     author = {G. A. Freiman},
     title = {On the addition of finite sets},
     journal = {Doklady Akademii Nauk},
     pages = {1038--1041},
     year = {1964},
     volume = {158},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_158_5_a8/}
}