[Sen et al. 2006] Sen, S., Lam, S. K., Rashid, A. M., Cosley, D., Frankowski, D., Osterhouse, J., Harper, F. M. and Riedl, J.: "tagging, communities, vocabulary, evolution"; CSCW '06: Proceedings of the 2006 20th anniversary conference on Computer supported cooperative work, ACM, New York, NY, USA (2006), 181--190.