@misc{1157766, author = {Gerald L Howett}, title = {Size of letters required for visibility as a function of viewing distance and observer visual acuity:}, year = {1983}, month = {1983-01-01 05:01:00}, publisher = {, National Institute of Standards and Technology, Gaithersburg, MD}, doi = {https://doi.org/10.6028/NBS.TN.1180}, language = {en}, }