@misc{indiciaec06367d34954,
  title = {Surface-state hydrogen maser.},
  author = {AC Maan and BJ Verhaar and HT Stoof and IF Silvera},
  year = {1993},
  doi = {10.1103/physreva.48.3921},
  url = {https://pubmed.ncbi.nlm.nih.gov/9910068/},
  note = {Source identifier: 9910068}
}