@misc{indiciae909a9faa7729,
  title = {Compact Microwave Mercury Ion Clock for Space Applications},
  author = {Prestage, John D. and Tu, Meirong and Chung, Sang K. and MacNeal, Paul},
  year = {2007},
  url = {https://ntrs.nasa.gov/citations/20090034988},
  note = {Source identifier: 20090034988}
}