Gennaro Costagliola Andrea De Lucia Sergio Orefice Giuseppe Polese A Classification Framework to Support the Design of Visual Languages. 573-600 2002 13 J. Vis. Lang. Comput. 6 http://dx.doi.org/10.1006/jvlc.2002.0234 db/journals/vlc/vlc13.html#CostagliolaLOP02