Husam Abu-Haimed Sergey Berezin David L. Dill Strengthening Invariants by Symbolic Consistency Testing. 407-419 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2725&spage=407 2003 conf/cav/2003 CAV db/conf/cav/cav2003.html#Abu-HaimedBD03