TY  - RPRT
TI  - Circular of the Bureau of Standards no. 6 4th edition: fees for electric, magnetic, and photometric testing
PY  - 1911
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 6e4
DO  - 10.6028/NBS.CIRC.6e4
ER  -