1. Agarwal, A., Izadi, S., Chandraker, M., Blake, A.: High Precision Multi-touch Sensing on Surfaces using Overhead Cameras. In: Proc. Tabletop 2007, pp. 197–200. IEEE Press, New York (2007)
2. BMBF, Bundesministerium für Bildung und Forschung: BrailleDis Project Presentation (2001), http://www.mstonline.de/foerderung/projektliste/detail_html?vb_nr=V2308
3. Edwards, A.D.N., Mitsopoulos, E.: A Principled Methodology for the Specification and Design of Nonvisual Widgets. ACM Transactions on Applied Perception 2(4), 442–449 (2006)
4. Ferres, L., Verkhogliad, P., Kindgaard, G., Boucher, L., Chretien, A., Lachance, M.: Improving Accessibility to Statistical Graphs: The iGraph-Lite System. In: ASSETS 2007: Proc. of the ACM Conference on Accessibility and Computers, pp. 67–74. ACM Press, New York (2007)
5. Heller, M.A.: The psychology of touch. Lawrence Erlbaum, Mahwah (1990)