(1)
Renzel, D.; Höbelt, C.; Dahrendorf, D.; Friedrich, M.; Mödritscher, F.; Verbert, K.; Govaerts, S.; Palmér, M.; Bogdanov, E. Collaborative Development of a PLE for Language Learning. Int. J. Emerg. Technol. Learn. 2010, 5, pp. 31-40.