Hana Chockler Arie Gurfinkel Ofer Strichman Beyond Vacuity: Towards the Strongest Passing Formula. 1-8 2008 FMCAD http://dx.doi.org/10.1109/FMCAD.2008.ECP.28 conf/fmcad/2008 db/conf/fmcad/fmcad2008.html#ChocklerGS08