Sasse, MA; Fentem, AC; (1994) Interacting with Multi-media, Multi-user Systems: Observations on Multi-Media Conferencing Tools. In: Proc. ECCE-7 Seventh European Conference on Cognitive Ergonomics. (pp. pp. 201-214). GMD (Gesellschaft fur Mathematik und Datenverarbeitung mbH): Bonn, Germany. Green open access