@misc{1172501, author = {F C Breckenridge}, title = {Color of signal lights ::their selection, definition, measurement, production, and use}, year = {1967}, month = {1967-01-01 05:01:00}, publisher = {, National Institute of Standards and Technology, Gaithersburg, MD}, doi = {https://doi.org/10.6028/NBS.MONO.75}, language = {en}, }