@article{MZM_2007_82_4_a6,
     author = {S. I. Dudov and A. B. Konoplev},
     title = {Approximation of {Continuous} {Set-Valued} {Maps} by {Constant} {Set-Valued} {Maps} with {Image} {Balls}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {525--529},
     publisher = {mathdoc},
     volume = {82},
     number = {4},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2007_82_4_a6/}
}