TY  - RPRT
TI  - Circular of the Bureau of Standards no. 42 2nd edition: metallographic testing
PY  - 1921
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 42e2
DO  - 10.6028/NBS.CIRC.42e2
ER  -