J. Huang, Z. Zhuang, J. Li, and C. Giles. Proceedings of the 2008 International Conference on Web Search and Data Mining, page 107--116. New York, NY, USA, ACM, (2008)
Y. Li, G. Kennedy, F. Davies, and J. Hunter. Proceedings of the role of digital libraries in a time of global change, and 12th international conference on Asia-Pacific digital libraries, page 179--188. Berlin, Heidelberg, Springer-Verlag, (2010)
C. Li. Mcgraw-Hill Professional, (2008)Charlene Li works for Forrester Research, a company well-known for its research on social media. "Web-Strategist" Jeremiah Owyang whose blog is among the top50 ad-blogs world-wide (http://www.web-strategist.com/blog) also works there as an analyst. I heartily recommend his blog if you're interested in social media and its impact on the business world..