Lars Engebretsen. The Nonapproximability of Non-Boolean Predicates. SIAM J. Discrete Math., 18(1):114-129, 2004. [doi]
@article{Engebretsen04,
title = {The Nonapproximability of Non-Boolean Predicates},
author = {Lars Engebretsen},
year = {2004},
doi = {10.1137/S0895480100380458},
url = {http://dx.doi.org/10.1137/S0895480100380458},
researchr = {https://researchr.org/publication/Engebretsen04},
cites = {0},
citedby = {0},
journal = {SIAM J. Discrete Math.},
volume = {18},
number = {1},
pages = {114-129},
}