@inproceedings{xu2013gathering,
  title={Gathering and generating paraphrases from twitter with application to normalization},
  author={Xu, Wei and Ritter, Alan and Grishman, Ralph},
  booktitle={Proceedings of the Sixth Workshop on Building and Using Comparable Corpora (BUCC)},
  pages={121--128},
  month     = {August},
  year      = {2013},
  address   = {Sofia, Bulgaria},
  publisher = {Association for Computational Linguistics},
  url={http://aclweb.org/anthology/W/W13/W13-2515.pdf}
}