@inproceedings{VoigtSwatman2006, author = {Voigt, Christian and Swatman, Paula}, title = {Online Case Discussions: Tensions in Activity Systems}, booktitle = {Sixth IEEE International Conference on Advanced Learning Technologies (ICALT'06), 05-07 July 2006, Kerkrade, The Netherlands}, pages = {748 -- 750}, doi = {10.1109/icalt.2006.1652550}, year = {2006}, }