Michael Rohs Georg Essl Johannes Schöning Anja Naumann Robert Schleicher Antonio Krüger Impact of item density on magic lens interactions. 2009 Mobile HCI http://doi.acm.org/10.1145/1613858.1613907 conf/mhci/2009 db/conf/mhci/mhci2009.html#RohsESNSK09