On Proper Unit Selection in Active Learning: Co-Selection Effects for Named Entity Recognition Katrin Tomanek author Florian Laws author Udo Hahn author Hinrich Schütze author 2009-06 text Proceedings of the NAACL HLT 2009 Workshop on Active Learning for Natural Language Processing Eric Ringger editor Robbie Haertel editor Katrin Tomanek editor Association for Computational Linguistics Boulder, Colorado conference publication tomanek-etal-2009-proper https://aclanthology.org/W09-1902/ 2009-06 9 17