Marek Meyer, Christoph Rensing, Ralf Steinmetz. Improving Authoring-by-Aggregation and Using Aggregation Context for Query Expansion. In Erik Duval, Ralf Klamma, Martin Wolpers, editors, Creating New Learning Experiences on a Global Scale, Second European Conference on Technology Enhanced Learning, EC-TEL 2007, Crete, Greece, September 17-20, 2007, Proceedings. Volume 4753 of Lecture Notes in Computer Science, pages 505-510, Springer, 2007. [doi]