J. Huang, Z. Zhuang, J. Li, und C. Giles. Proceedings of the 2008 International Conference on Web Search and Data Mining, Seite 107--116. New York, NY, USA, ACM, (2008)
X. Wen, Y. Lin, C. Trattner, und D. Parra. Proceedings of the 25th ACM Conference on Hypertext and Social Media, Seite 285--290. New York, NY, USA, ACM, (2014)