@misc{indiciaef78270f76009,
  title = {Density-dependent frequency shift of the hydrogen S2/1/ quadrupole line},
  author = {Chackerian, C., Jr. and Giver, L. P.},
  year = {1975},
  url = {https://ntrs.nasa.gov/citations/19760038825},
  note = {Source identifier: 19760038825}
}