TY  - RPRT
TI  - Letter Circular 609: list of commercial standards (supersedes Letter Circular 604)
PY  - 1940
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 609r1940
DO  - 10.6028/NBS.LCIRC.609r1940
ER  -