Alberto Bemporad Nicolò Giorgetti SAT-Based Branch & Bound and Optimal Control of Hybrid Dynamical Systems. 96-111 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3011&spage=96 2004 conf/cpaior/2004 CPAIOR db/conf/cpaior/cpaior2004.html#BemporadG04