1. Boissière, P., Dours, D.: VITIPI: versatile interpretation of text input by persons with impairments. In: Proc. 5th International Conference on Computers for Handicapped Persons, ICCHP 1996, Linz, Autriche, pp. 165–173 (1996)
2. Wandmacher, T., Antoine, J.-Y., Poirier, F., Departe, J.-P.: SIBYLLE, An Assistive Communication System Adapting to the Context and Its User. ACM Transactions on Accessible Computing 1(1), 1–30 (2008)
3. Lecture Notes in Computer Science;D. Maurel,1999
4. Keystrokes on-screen keyboard, user manual,
http://www.assistiveware.com/files/KeyStrokesXmanualA4.pdf
5. Miller, G.: The Magical Number Seven, Plus or Minus Two. The Psychological Review 63(2), 81–97 (1956)