@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} }