Gerrit Renker Hatem Ahriz Inés Arana A Synergy of Modelling for Constraint Problems. 1030-1038 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2773&spage=1030 2003 conf/kes/2003-1 KES db/conf/kes/kes2003-1.html#RenkerAA03