@misc{1190526, author = {F C Breckenridge}, title = {United States standard for the colors of signal lights:}, 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.HB.95}, language = {en}, }