Frank Steinicke Timo Ropinski Gerd Bruder Klaus Hinrichs Interscopic User Interface Concepts for Fish Tank Virtual Reality Systems. 27-34 2007 VR http://doi.ieeecomputersociety.org/10.1109/VR.2007.352460 conf/vr/2007 db/conf/vr/vr2007.html#SteinickeRBH07