A. Kittur, E. Chi, und B. Suh. CHI '08: Proceeding of the twenty-sixth annual SIGCHI conference on Human factors in computing systems, Seite 453--456. New York, NY, USA, ACM, (2008)
M. Andreasen, H. Nielsen, S. Schrøder, und J. Stage. CHI '07: Proceedings of the SIGCHI conference on Human factors in computing systems, Seite 1405--1414. New York, NY, USA, ACM, (2007)