TY  - RPRT
TI  - Letter Circular 199: selenium cells; photoelectric cells; thermopiles
PY  - 1930
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 199r1930
DO  - 10.6028/NBS.LCIRC.199r1930
ER  -