E. Jensen, S. Beitzel, O. Frieder, und A. Chowdhury. Special interest tracks and posters of the 14th international conference on World Wide Web, Seite 1176--1177. New York, NY, USA, ACM, (2005)
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)