@conference{4526,
  author = {D. Allan and Judah Levine},
  title = {A rubidium frequency standard and a GPS receiver. A remotely steered clock system with good short-term and long-term stability},
  year = {1990},
  publisher = {IEEE},
  address = {Baltimore, MD, USA},
  doi = {10.1109/FREQ.1990.177493},
}