@misc{1166806,
  author = {F C Breckenridge},
  title = {Background and objectives of the U.S. Standard for the colors of signal lights:},
  year = {1959},
  month = {1959-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.RPT.6413},
  language = {en},
}