S.  Manske, Hecking, T., Chounta, I. - A., Werneburg, S., und Hoppe, H. Ulrich, ?Using Differences to Make a Difference: A Study on Heterogeneity of Learning Groups?, in 11th International Conference on Computer Supported Collaborative Learning, CSCL 2015, Gothenburg, Sweden, June 7-11, 2015, 2015.