@article{MAT_1967_11_2_a3,
     author = {P. Erd\H{o}s},
     title = {Extremal problems in number theory},
     journal = {Matematika},
     pages = {98--105},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1967_11_2_a3/}
}