TY  - RPRT
TI  - Improvement of visual aids for air navigation : progress report March 1, 1954 to June 30, 1954
AU  - Breckenridge, F C
PY  - 1954
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS report ; 3647
DO  - 10.6028/NBS.RPT.3647
ER  -