L. Wu, X. Huang, L. You, Z. Zhang, X. Li, and Y. Zhou. TREC, volume 500-261 of NIST Special Publication, National Institute of Standards and Technology (NIST), (2004)
L. Wu, X. Huang, Y. Zhou, Y. Du, and L. You. TREC, volume 500-255 of NIST Special Publication, page 246-253. National Institute of Standards and Technology (NIST), (2003)