TY  - RPRT
TI  - Circular of the Bureau of Standards no. 25 4th edition: standard analyzed samples- general information
PY  - 1912
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 25e4
DO  - 10.6028/NBS.CIRC.25e4
ER  -