R. White, M. Bilenko, and S. Cucerzan. Proceedings of the 30th annual international ACM SIGIR conference on Research and development in information retrieval, page 159--166. ACM, (2007)
P. Singer, D. Helic, A. Hotho, and M. Strohmaier. International Conference on World Wide Web, page 1003--1013. Republic and Canton of Geneva, Switzerland, International World Wide Web Conferences Steering Committee, (2015)