@misc{1169636,
  author = {W R Knight},
  title = {How many guards?:},
  year = {1952},
  month = {1952-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.RPT.1834},
  language = {en},
}