TY  - RPRT
TI  - Letter Circular 537: railway track scale testing service of the National Bureau of Standards fiscal year 1938 (July 1, 1937 to June 30, 1938)
PY  - 1938
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 537
DO  - 10.6028/NBS.LCIRC.537
ER  -