S. Kim, C. Robson, T. Zimmerman, J. Pierce, and E. Haber. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 2125--2134. New York, NY, USA, ACM, (2011)
E. Brady, Y. Zhong, M. Morris, and J. Bigham. Proceedings of the 2013 Conference on Computer Supported Cooperative Work, page 1225--1236. New York, NY, USA, ACM, (2013)