@article{DAN_1982_265_2_a5,
     author = {N. V. Ivanov},
     title = {Entropy and {Nielsen} numbers},
     journal = {Doklady Akademii Nauk},
     pages = {284--287},
     year = {1982},
     volume = {265},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1982_265_2_a5/}
}