A Comparative Study of Open Domain and Opinion Question Answering Systems for Factual and Opinionated Queries Alexandra Balahur author Ester Boldrini author Andrés Montoyo author Patricio Martínez-Barco author 2009-09 text Proceedings of the International Conference RANLP-2009 Galia Angelova editor Ruslan Mitkov editor Association for Computational Linguistics Borovets, Bulgaria conference publication balahur-etal-2009-comparative https://aclanthology.org/R09-1004/ 2009-09 18 22