@article{102731,
  author = {James Bergquist and Steven Jefferts and David Wineland},
  title = {Time Measurement at the Millennium},
  year = {2001},
  number = {54},
  month = {2001-03-01},
  publisher = {Physics Today},
  url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=105140},
  language = {en},
}