Frank Schmiedle Rolf Drechsler Bernd Becker Exact channel routing using symbolic representation. 394-397 1999 conf/iscas/1999 ISCAS (6) http://doi.ieeecomputersociety.org/10.1109/ISCAS.1999.780178 db/conf/iscas/iscas1999-6.html#SchmiedleDB99