T. Karp, and R. Gale. Proceedings of the 39th IEEE international conference on Frontiers in education conference, page 308--312. Piscataway, NJ, USA, IEEE Press, (2009)
B. Maxim, and B. Elenbogen. Proceedings of the 39th IEEE international conference on Frontiers in education conference, page 119--123. Piscataway, NJ, USA, IEEE Press, (2009)