TY  - RPRT
TI  - Letter Circular 431: railway track scale testing service of the National Bureau of Standards fiscal year July 1, 1933 to June 30, 1934
PY  - 1934
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 431
DO  - 10.6028/NBS.LCIRC.431
ER  -