The following paper was one of my presentation references:
Shen, C., Ryall, K., Forlines, C., Esenther, A., Vernier, F. D., Everitt, K., Wu, M., Wigdor, D., Morris, M. R., Hancock, M., and Tse, E. 2006. Informing the Design of Direct-Touch Tabletops. IEEE Comput. Graph. Appl. 26, 5 (Sep. 2006), 36-46.
Clifton Forlines, one of the paper's authors, is a researcher at Mitsubishi. He's posted all of his research papers, as well as links to video clips related to table top computing, all on one page: http://www.cliftonforlines.com/publications.php