D. Sun, and W. Lau. Pervasive Computing and Communications Workshops (PERCOM Workshops), 2013 IEEE International Conference on, page 205-210. (March 2013)
W. Tang, H. Zhuang, and J. Tang. Proceedings of the ECML/PKDD 2011, volume 6913 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2011)