Ombretta Gaggi Augusto Celentano A Visual Authoring Environment for Prototyping Multimedia Presentations. 206-213 2002 conf/mse/2002 ISMSE http://csdl.computer.org/comp/proceedings/mse/2002/1857/00/18570206abs.htm db/conf/mse/ismse2002.html#GaggiC02