TY  - RPRT
TI  - Circular of the Bureau of Standards no. 497: 
AU  - Schoonover, I C
PY  - 1950
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 497
DO  - 10.6028/NBS.CIRC.497
ER  -