I. Marenzi, S. Zerr, F. Abel, and W. Nejdl. International Journal of Continuing Engineering Education and Life-Long Learning (IJCEELL), 19 (4/5/6):
276-290(2009)
K. Bischoff, C. Firan, W. Nejdl, and R. Paiu. Journal of Web Semantics: Science, Services and Agents on the World Wide Web Volume, 8(2-3), 97-109, 2010., (2010)