Steven C. Seow Dennis R. Wixon Scott MacKenzie Giulio Jacucci Ann Morrison Andy Wilson Multitouch and surface computing. 4767-4770 2009 CHI Extended Abstracts http://doi.acm.org/10.1145/1520340.1520736 conf/chi/2009a db/conf/chi/chi2009a.html#SeowWMJMW09