@conference{63406,
  author = {Thomas Parker},
  title = {Performance of a Hydrogen Maser Ensemble and Characterization of Frequency Standards},
  year = {1999},
  month = {1999-01-01},
  publisher = {IEEE Trans. Ultrason. Ferroelec. Freq. Cont., Besan{c-cedilla}on, FR},
  url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=105535},
  language = {en},
}