@misc{indiciaeaea446cd6673,
  title = {Timekeeping: light-insensitive optical clock.},
  author = {Thomas Udem},
  year = {2005},
  doi = {10.1038/435291a},
  url = {https://pubmed.ncbi.nlm.nih.gov/15902244/},
  note = {Source identifier: 15902244}
}