F. Mitzlaff, M. Atzmueller, D. Benz, A. Hotho, and G. Stumme. Analysis of Social Media and Ubiquitous Data, volume 6904 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2011)
W. Xi, E. Fox, W. Fan, B. Zhang, Z. Chen, J. Yan, and D. Zhuang. SIGIR '05: Proceedings of the 28th annual international ACM SIGIR conference on Research and development in information retrieval, page 130--137. New York, NY, USA, ACM, (2005)