Boris Litvak Shmuel S. Tyszberowicz Amiram Yehudai Behavioral Consistency Validation of UML Diagrams. 118-125 2003 conf/sefm/2003 SEFM http://csdl.computer.org/comp/proceedings/sefm/2003/1949/00/19490118abs.htm db/conf/sefm/sefm2003.html#LitvakTY03