Tim de Jong, Marcus Specht and Rob Koper Wenger, E., & Lave, J. (1991). Situated Learning: Legitimate peripheral participation. Cambridge, New York: Cambridge University Press. Yatani, K., Sugimoto, M., & Kusunoki, F. (2004). Musex: a system for supporting children's collaborative learning in a museum with PDAs. Paper presented at the The 2nd IEEE International Workshop on Wireless and Mobile Technologies in Education (WMTE '04). Zielke, L. (2005). Entwicklung und Evaluation eines kontextbasierten mobilen Spiels unter Einbeziehung verschiedener Lokalisierungsverfahren. Unpublished Master, Fachhochschule Oldenburg, Wilhelmshaven. Zimmermann, A., Lorenz, A., & Oppermann, R. (2007). An Operational Definition of Context. Paper presented at the Context 07. Zimmermann, A., Lorenz, A., & Specht, M. (2005). Personalization and Context-Management. User Modeling and User Adaptive Interaction (UMUAI), Special Issue on User Modeling in Ubiquitous Computing, 15(3-4), 275-302. Zimmermann, A., Specht, M., & Lorenz, A. (2005). Personalization and Context Management. User Modeling and User-Adapted Interaction, 15, 275-302.