@misc{1129161,
  author = {E M Voorhees and D K Harman},
  title = {The ninth text REtrieval conference (TREC-9):},
  year = {2001},
  month = {2001-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NIST.SP.500-249},
  language = {en},
}