Hans S. Witsenhausen. The zero-error side information problem and chromatic numbers (Corresp.). IEEE Transactions on Information Theory, 22(5):592-593, 1976. [doi]
@article{Witsenhausen76-0,
title = {The zero-error side information problem and chromatic numbers (Corresp.)},
author = {Hans S. Witsenhausen},
year = {1976},
doi = {10.1109/TIT.1976.1055607},
url = {http://doi.ieeecomputersociety.org/10.1109/TIT.1976.1055607},
researchr = {https://researchr.org/publication/Witsenhausen76-0},
cites = {0},
citedby = {0},
journal = {IEEE Transactions on Information Theory},
volume = {22},
number = {5},
pages = {592-593},
}