Hyunyoung Song Tovi Grossman George W. Fitzmaurice François Guimbretière Azam Khan Ramtin Attar Gordon Kurtenbach PenLight: combining a mobile projector and a digital pen for dynamic visual overlay. 143-152 2009 CHI http://doi.acm.org/10.1145/1518701.1518726 conf/chi/2009 db/conf/chi/chi2009.html#SongGFGKAK09