Levels of certainty in knowledge-intensive corpora: an initial annotation study Aron Henriksson author Sumithra Velupillai author 2010-07 text Proceedings of the Workshop on Negation and Speculation in Natural Language Processing Roser Morante editor Caroline Sporleder editor University of Antwerp Uppsala, Sweden conference publication henriksson-velupillai-2010-levels https://aclanthology.org/W10-3107/ 2010-07 41 45