TY  - RPRT
TI  - Letter Circular 256A: sources of supply of commodities covered by federal specifications
PY  - 1930
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 256Ar1930
DO  - 10.6028/NBS.LCIRC.256Ar1930
ER  -