The Approximability of Three-valued MAX CSP. - Peter Jonsson; Mikael Klasson; Andrei A. Krokhin (SIAM J. Comput., 2006)

The approximability of MAX CSP with fixed-value constraints. - Vladimir G. Deineko; Peter Jonsson; Mikael Klasson; Andrei A. Krokhin (J. ACM, 2008)