C. Neuwirth, D. Kaufer, R. Chandhok, and J. Morris. Proceedings of the 1990 ACM conference on Computer-supported cooperative work, page 183--195. New York, NY, USA, ACM, (1990)
C. Neuwirth, D. Kaufer, R. Chandhok, and J. Morris. CSCW '90: Proceedings of the 1990 ACM conference on Computer-supported cooperative work, page 183--195. New York, NY, USA, ACM Press, (1990)
A. Kittur, B. Suh, and E. Chi. CSCW '08: Proceedings of the ACM 2008 conference on Computer supported cooperative work, page 477--480. New York, NY, USA, ACM, (2008)
P. Carstensen, and K. Schmidt. Handbook of Human Factors, Asakura Publishing, in Japanese, English Version available from http://www.itu.dk/people/schmidt/publ.html.(1999)