@inbook { stratmann_das_20, title = {Das Studienportal der Universit{\"a}t Duisburg-Essen}, booktitle = {Bildungsportale - Potenziale und Perspektiven netzbasierter Bildungsressourcen}, year = {2007}, publisher = {Oldenbourg}, organization = {Oldenbourg}, address = {M{\"u}nchen}, author = {Stratmann, J{\"o}rg and Michael Kerres}, editor = {Gaiser, Birgit and Hesse, Friedrich W. and Monika L{\"u}tke-Entrup} }