@misc{1198396,
  author = {Gwen E Bennett},
  title = {Time & frequency bulletin No. 397:},
  year = {1990},
  month = {1990-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NIST.IR.90-3940-12},
  language = {en},
}