Rolf Drechsler Marc Herbstritt Bernd Becker Grouping heuristics for word-level decision diagrams. 411-414 1999 conf/iscas/1999 ISCAS (1) http://doi.ieeecomputersociety.org/10.1109/ISCAS.1999.777893 db/conf/iscas/iscas1999-1.html#DrechslerHB99