@inproceedings{Purver-etAl:2003:SIGDIAL,
  author = {Purver, Matthew  and  Healey, Patrick G.T.  and  King, James  and  Ginzburg, Jonathan  and  Mills, Greg J.},
  title = {Answering Clarification Questions},
  booktitle = {Proceedings of the Fourth {SIGdial} Workshop on Discourse and Dialogue},
  editor = {Akira Kurematsu and Alexander Rudnicky and Syun Tutiya},
  url = {http://www.aclweb.org/anthology/W03-2103},
  year = 2003,
  pages = {23--33}