wbo1.6 is an unsatisfiability-based algorithm for MaxSAT, pseudo-Boolean and WBO. References: V. Manquinho, R. Martins, I. Lynce, Improving Unsatisfiability-Based Algorithms for Boolean Optimization, SAT 2010. V. Manquinho, J. Marques-Silva, J. Planes, Algorithms for Weighted Boolean Optimization, SAT 2009.