1. School of Informatics, University of Skövde, Skövde, Sweden
2. School of Informatics, University of Skövde, Skövde, Sweden & Department of Information Technology, Visual Information and Interaction, Uppsala University, Uppsala, Sweden
3. School of Informatics, University of Skövde, Skövde, Sweden & Department of Computer and Information Science, Linköping University, Linköping, Sweden