S. Lindley, J. Couteur, and N. Berthouze. (2008)CHI 2008: Computer-Human Interaction Conference on Human Factors in Computing Systems, Florence, Italy, 5 - 10 April, 2008. Session: I am here. Where are you?.
P. Kabbash, S. Mackenzie, and W. Buxton. CHI '93: Proceedings of the SIGCHI conference on Human factors in computing systems, page 474--481. New York, NY, USA, ACM Press, (1993)