E. Ferrara, O. Varol, F. Menczer, and A. Flammini. Proceedings of the first ACM Conference on Online Social Networks, page 213--222. New York, NY, USA, ACM, (2013)
Y. Li, A. Wen, Q. Lin, R. Li, and Z. Lu. Web-Age Information Management, volume 6897 of Lecture Notes in Computer Science, Springer, Berlin/Heidelberg, (2011)