M. Ames, and M. Naaman. CHI '07: Proceedings of the SIGCHI conference on Human factors in computing systems, page 971--980. New York, NY, USA, ACM, (2007)
A. Rivadeneira, D. Gruen, M. Muller, and D. Millen. CHI '07: Proceedings of the SIGCHI conference on Human factors in computing systems, page 995--998. New York, NY, USA, ACM, (2007)