@InProceedings{lloret-EtAl:2009:SRWS,
  author    = {Lloret, Elena  and  Balahur, Alexandra  and  Palomar, Manuel  and  Montoyo, Andr\'{e}s},
  title     = {Towards Building a Competitive Opinion Summarization System: {C}hallenges and Keys},
  booktitle = {Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics, Companion Volume: Student Research Workshop and Doctoral Consortium},
  month     = {June},
  year      = {2009},
  address   = {Boulder, Colorado},
  publisher = {Association for Computational Linguistics},
  pages     = {72--77},
  url       = {http://www.aclweb.org/anthology/N/N09/N09-3013}
}