@conference{6775,
  author = {L. Nelson and Judah Levine and T. Parker and K. Larson and P. Hetzel and J. Becker},
  title = {Comparison of atomic frequency standards at NIST and PTB using carrier-phase GPS},
  year = {1999},
  month = {1999-12},
  url = {http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2\&doc=GetTRDoc.pdf\&AD=ADA497323},
  note = {JILA Pub. 6514},
}