M. Mavrikis, and S. Gutierrez-Santos. Computers & Education, 54 (3):
641 - 651(2010)Learning in Digital Worlds: Selected Contributions from the CAL 09 Conference.
G. Biegel, and V. Cahill. Proceedings of the Second IEEE International Conference on Pervasive Computing and Communications (PerCom'04), page 361--. Washington, DC, USA, IEEE Computer Society, (2004)