Jean-Rémi Bourguet Bernard Cuq Amadou Ndiaye Rallou Thomopoulos Modelling a Dynamic Process in the Conceptual Graph Model: Extension Needed? 49-56 2008 ICCS Supplement http://ceur-ws.org/Vol-354/p35.pdf conf/iccs/2008s db/conf/iccs/iccss2008.html#BourguetCNT08