@article{MZM_2001_69_2_a13,
     author = {A. R. Alimov and M. I. Karlov},
     title = {Sets with {External} {Chebyshev} {Layer}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {303--307},
     publisher = {mathdoc},
     volume = {69},
     number = {2},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2001_69_2_a13/}
}