@misc{indiciaebe6b0b8b3ea8,
  title = {Ultrastable-frequency distribution system},
  author = {Macconnell, J. W. and Sydnor, R. L.},
  year = {1977},
  url = {https://ntrs.nasa.gov/citations/19770000031},
  note = {Source identifier: 19770000031}
}