@misc{1156561,
  author = {Robert J Carpenter},
  title = {A portable rubidium-vapor frequency standard.:},
  year = {1964},
  month = {1964-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.TN.235},
  language = {en},
}