A. Wichmann, A. Giemza, M. Krauß, and H. Hoppe. Proceedings of the 8th International Conference on Computer Supported Collaborative Learning (CSCL 2009), Rhodes, Greece, (June 2009)
K. Ala-Mutka, M. Bacigalupo, S. Kluzer, C. Pascu, Y. Punie, and C. Redecker. Report on a validation and policy options workshop organised by IPTS Seville, 29-30 October 2008, EUR 23786 EN. Office for Official Publications of the European Communities, Luxembourg, (2009)