Ateet Bhalla Inês Lynce José T. de Sousa João P. Marques Silva Heuristic-Based Backtracking for Propositional Satisfiability. 116-130 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2902&spage=116 2003 conf/epia/2003 EPIA db/conf/epia/epia2003.html#BhallaLSM03