@article{DAN_1961_141_3_a14,
     author = {G. A. Freiman},
     title = {Inverse problems in additive number theory. {Addition} of sets of residues modulo a prime},
     journal = {Doklady Akademii Nauk},
     pages = {571--573},
     publisher = {mathdoc},
     volume = {141},
     number = {3},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_141_3_a14/}
}