@article{179771,
  author = {Steven Jefferts and Thomas Heavner and Elizabeth Donley},
  title = {Cesium Primary Frequency References},
  year = {2007},
  number = {21},
  month = {2007-02-01},
  publisher = {J. Metrol. Soc. India},
  url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50448},
  language = {en},
}