Figure 2.3 © ACM, 1992.
Figure 2.5 Photo used by permission of Charles Rencsok.
Figure 4.2 Reprinted with permission from Ho, Powell, and Liley. Journal of Physical and Chemical Reference Data 3, Supplement, 1, 1974, American Institute of Physics and National Institute of Science and Technology.
Figure 4.7 © Graphics Press.
Figure 4.8 Courtesy of Human-Computer Interaction Laboratory, University
of Maryland, College Park, MD. Figure 9.3 © ACM, 1994.
Figure 9.4 Greenberg, S. and Gutwin, C. (1998) From Technically Possible to Socially Natural Groupware. In Proceedings of the 9th NEC Research Symposium: The Human-centric Multimedia Community. August 31-September 1, Nara, Japan.
Figure 9.6 Courtesy of the ACM from the project of Justine ...