@inproceedings{Sudo:2003:ACL,
  author = {Sudo, Kiyoshi  and  Sekine, Satoshi  and  Grishman, Ralph},
  title  = {An Improved Extraction Pattern Representation Model for Automatic {IE} Pattern Acquisition},
  booktitle = {Proceedings of the 41st Annual Meeting of the Association for Computational Linguistics},
  editor = {Erhard Hinrichs and Dan Roth},
  url    = {http://www.aclweb.org/anthology/P03-1029.pdf},
  year   = 2003,
  pages  = {224--231}
}