J. Burkhardt, F. Détienne, A. Hébert, L. Perron, S. safin, and P. Leclercq. European Conference on Cognitive Ergonomics: Designing beyond the Product — Understanding Activity and User Experience in Ubiquitous Environments, page 30:1–30:9. VTT, Finland, Finland, VTT Technical Research Centre of Finland, (2009)
G. Stahl. Proceedings of the Conference on Computer Support for Collaborative Learning: Foundations for a CSCL Community, page 62–71. International Society of the Learning Sciences, (2002)