Augusto Celentano Daniela Fogli Piero Mussio Fabio Pittarello Virtual Reality Interaction: The Characteristic Pattern Approach. 48-50 2002 IEEE Symposia on Human Centric Computing Languages and Environments http://computer.org/proceedings/hcc/1644/16440048abs.htm db/conf/hccl/hccl2002.html#CelentanoFMP02