M. Akbarzadeh-T., E. Tunstel, K. Kumbla, and M. Jamshidi. Proceedings of the 1998 IEEE World Congress on
Computational Intelligence, 2, page 1200--1205. Anchorage, Alaska, USA, IEEE Press, (5-9 May 1998)
J. West, A. Haake, E. Rozanski, and K. Karn. ETRA '06: Proceedings of the 2006 symposium on Eye tracking research
& applications, page 149--154. New York, NY, USA, ACM Press, (2006)
S. Ajitha, T. Kumar, D. Geetha, and K. Kanth. 2010 International Conference on Industrial and Information Systems (ICIIS), page 372--376. IEEE, (August 2010)