@article{DAN_1960_132_5_a0,
     author = {S. Ya. Al'per},
     title = {$\varepsilon${-Entropy} of certain classes of functions},
     journal = {Doklady Akademii Nauk},
     pages = {977--979},
     year = {1960},
     volume = {132},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_132_5_a0/}
}