@misc{indiciae1aa9e8b831b9,
  title = {Hydrogen-maser principles and techniques.},
  author = {Berg, H. C. and Crampton, S. B. and Kleppner, D. and Peters, H. E. and Ramsey, N. F. and Vanier, J. and Vessot, R. F. C.},
  year = {1965},
  url = {https://ntrs.nasa.gov/citations/19650041605},
  note = {Source identifier: 19650041605}
}