Edmund M. Clarke Helmut Veith Counterexamples Revisited: Principles, Algorithms, Applications. 208-224 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2772&spage=208 2003 conf/birthday/2003manna Verification: Theory and Practice db/conf/birthday/Manna2003.html#ClarkeV03