TY  - RPRT
TI  - Circular of the Bureau of Standards no. 552: standard samples and reference standards issued by the National Bureau of Standards
PY  - 1954
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 552
DO  - 10.6028/NBS.CIRC.552
ER  -