Marino Miculan Kidane Yemane A Unifying Model of Variables and Names. 170-186 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3441&spage=170 2005 conf/fossacs/2005 FoSSaCS db/conf/fossacs/fossacs2005.html#MiculanY05