N. Weibel, A. Fouse, E. Hutchins, and J. Hollan. Proceedings of the 16th International Conference on Intelligent User Interfaces, page 257--266. New York, NY, USA, ACM, (2011)
A. Yousef, M. Chatti, U. Schroeder, and M. Wosnitza. Advanced Learning Technologies (ICALT), 2014 IEEE 14th International Conference on, page 44--48. IEEE, IEEE Computer Society, (2014)
M. Rubini, P. Selvy, and M. Prabha. International Journal of Computer Science, Engineering and Information Technology (IJCSEIT), 2 (1):
45-55(February 2012)