C. Cattuto, D. Benz, A. Hotho, and G. Stumme. ISWC '08: Proceedings of the 7th International Conference on The Semantic Web, page 615--631. Berlin, Heidelberg, Springer-Verlag, (2008)
E. Chi, and T. Mytkowicz. HT '08: Proceedings of the nineteenth ACM conference on Hypertext and hypermedia, page 81--88. New York, NY, USA, ACM, (2008)