@article{DAN_1961_140_3_a1,
     author = {N. V. Efimov and S. B. Stechkin},
     title = {Approximative compactness and {Chebyshev} sets},
     journal = {Doklady Akademii Nauk},
     pages = {522--524},
     publisher = {mathdoc},
     volume = {140},
     number = {3},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_140_3_a1/}
}