1. Anoto, Inc. (2005) ,Website http://www.anoto.com
2. Discrete Trial Trainer (DTT) Columbia, SC. (2004) http://www.dttrainer.com
3. Nexidia, Inc. (2005) , Website in http://www.nexidia.com
4. Alberto, P.A., Troutman, A.C.: Applied Behavior Analysis for Teachers, 6th edn. Prentice Hall, Englewood Cliffs (2003)
5. Arnstein, L., et al.: Labscape: A Smart Environment for the Cell Biology Laboratory. IEEE Pervasive Computing Magazine (2002)