Barney Reiffen. A per letter converse to the channel coding theorem. IEEE Transactions on Information Theory, 12(4):475-480, 1966. [doi]
@article{Reiffen66,
title = {A per letter converse to the channel coding theorem},
author = {Barney Reiffen},
year = {1966},
doi = {10.1109/TIT.1966.1053928},
url = {http://dx.doi.org/10.1109/TIT.1966.1053928},
researchr = {https://researchr.org/publication/Reiffen66},
cites = {0},
citedby = {0},
journal = {IEEE Transactions on Information Theory},
volume = {12},
number = {4},
pages = {475-480},
}