Ateet Bhalla Inês Lynce José T. de Sousa João Marques-Silva Heuristic-Based Backtracking Relaxation for Propositional Satisfiability. 3-24 2005 35 J. Autom. Reasoning 1-3 http://dx.doi.org/10.1007/s10817-005-9005-y db/journals/jar/jar35.html#BhallaLSM05