R. Yan, M. Lapata, and X. Li. Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics: Long Papers - Volume 1, page 516--525. Stroudsburg, PA, USA, Association for Computational Linguistics, (2012)
S. Robertson, S. Walker, and M. Hancock-Beaulieu. TREC, Special Publication 500-242, page 199-210. National Institute of Standards and Technology (NIST), (1998)
D. Pighin, M. Cornolti, E. Alfonseca, and K. Filippova. Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), page 892--901. Baltimore, Maryland, Association for Computational Linguistics, (June 2014)