Towards High-Quality Text Stream Extraction from PDF. Technical Background to the ACL 2012 Contributed Task Øyvind Raddum Berg author Stephan Oepen author Jonathon Read author 2012-07 text Proceedings of the ACL-2012 Special Workshop on Rediscovering 50 Years of Discoveries Rafael E Banchs editor Association for Computational Linguistics Jeju Island, Korea conference publication berg-etal-2012-towards https://aclanthology.org/W12-3211/ 2012-07 98 103