K. Balog. SIGIR '07: Proceedings of the 30th annual international ACM SIGIR conference on Research and development in information retrieval, page 916--916. New York, NY, USA, ACM, (2007)
K. Balog, L. Azzopardi, and M. de Rijke. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, page 43--50. New York, NY, USA, ACM, (2006)