1. Apteker, R. and Fischer, J. and Kisimov, V. and Neishols, H. (1995) Video acceptability and frame rate IEEE Multimedia, 2, pp. 32 - 40.
2. Argyle, M. and Lalljee, M. and Cook, M. (1968) The effects of visibility on interaction in the dyad Human Relations, 28, pp. 289 - 304.
3. Bruce, V. (1996) The role of the face in communication: implications for videophone design Interacting with Computers, 8, pp. 166 - 176.
4. Clark, H. and Brennan, S.(1991) Grounding in communication. In Perspectives on Socially Shared Cognition. . Washington DC: APA Press.
5. Clark, H. and Schaefer, E. (1989) Contributing to discourse Cognitive Science, 12, pp. 259 - 292.