TY  - RPRT
TI  - Circular of the Bureau of Standards no. 431: typewriter ribbons and carbon paper
AU  - Waters, C E
PY  - 1941
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 431
DO  - 10.6028/NBS.CIRC.431
ER  -