G. Ruß, R. Kruse, M. Schneider, and P. Wagner. Artificial Intelligence in Theory and Practice II, volume 276 of IFIP International Federation for Information Processing, Springer, (July 2008)
A. Anand, M. Khosla, J. Singh, J. Zab, and Z. Zhang. Proceedings of the Twelfth ACM International Conference on Web Search and Data Mining, page 168--176. (2019)