@article{DAN_1961_140_6_a10,
     author = {V. I. Levenshtein},
     title = {Certain properties of code systems},
     journal = {Doklady Akademii Nauk},
     pages = {1274--1277},
     publisher = {mathdoc},
     volume = {140},
     number = {6},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_140_6_a10/}
}