S. Sen, J. Vig, и J. Riedl. IUI '09: Proceedings of the 13th international conference on Intelligent user interfaces, стр. 87--96. New York, NY, USA, ACM, (2009)
Y. Song, Z. Zhuang, H. Li, Q. Zhao, J. Li, W. Lee, и C. Giles. Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval, стр. 515--522. New York, NY, USA, ACM, (2008)