Mitra Purandare Thomas Wahl Daniel Kroening Strengthening properties using abstraction refinement. 1692-1697 2009 DATE http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=5090609&arnumber=5090935&count=326&index=321 conf/date/2009 db/conf/date/date2009.html#PurandareWK09