@article{206836,
  author = {G Wilpers and Christopher Oates and Scott Diddams and A Bartels and Tara Fortier and Windell Oskay and James Bergquist and Steven Jefferts and Thomas Heavner and Thomas Parker and Leo Hollberg},
  title = {Absolute frequency measurement of the neutral <sup>40</sup>Ca optical frequency standard at 657 nm based on microkelvin atoms},
  year = {2007},
  number = {44},
  month = {2007-03-14},
  publisher = {Metrologia},
  url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50474},
  language = {en},
}