Sriram Sankaranarayanan Henny Sipma Zohar Manna Non-linear loop invariant generation using Gröbner bases. 318-329 2004 conf/popl/2004 POPL http://doi.acm.org/10.1145/964001.964028 db/conf/popl/popl2004.html#SankaranarayananSM04