TY  - RPRT
TI  - Circular of the Bureau of Standards no. 25 7th edition: standard samples- general information
PY  - 1922
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 25e7
DO  - 10.6028/NBS.CIRC.25e7
ER  -