H. Forssell. (2011)cite arxiv:1109.0699Comment: 32 pages. This is the first pre-print version, the final revised version can be found at http://onlinelibrary.wiley.com/doi/10.1002/malq.201100080/abstract (posting of which is not allowed by Wiley). Changes in v2: updated comments.
D. Spikol, and J. Eliasson. The 6th IEEE International Conference on Wireless, Mobile, and Ubiquitous Technologies in Education, page 137--141. IEEE, (2010)