Paola Carrara Daniela Fogli Giuseppe Fresta Piero Mussio Making Abstract Specifications Concrete to End-Users: The Visual Workshop Hierarchy Strategy. 43- 2002 IEEE Symposia on Human Centric Computing Languages and Environments http://computer.org/proceedings/hcc/1644/16440043abs.htm db/conf/hccl/hccl2002.html#CarraraFFM02