Extending HeidelTime for Temporal Expressions Referring to Historic Dates Jannik Strötgen author Thomas Bögel author Julian Zell author Ayser Armiti author Tran Van Canh author Michael Gertz author 2014-05 text Proceedings of the Ninth International Conference on Language Resources and Evaluation (LREC’14) Nicoletta Calzolari editor Khalid Choukri editor Thierry Declerck editor Hrafn Loftsson editor Bente Maegaard editor Joseph Mariani editor Asuncion Moreno editor Jan Odijk editor Stelios Piperidis editor European Language Resources Association (ELRA) Reykjavik, Iceland conference publication strotgen-etal-2014-extending https://aclanthology.org/L14-1655/ 2014-05 2390 2397