@article{DAN_1967_172_2_a11,
     author = {S. Ya. Havinson},
     title = {Approximation by elements of convex sets},
     journal = {Doklady Akademii Nauk},
     pages = {294--297},
     publisher = {mathdoc},
     volume = {172},
     number = {2},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_172_2_a11/}
}