TY  - RPRT
TI  - Sky luminance and direct beam illuminance 
AU  - Treado, S
AU  - Remmert, W
AU  - Bean, J
PY  - 1986
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 85-3251
DO  - 10.6028/NBS.IR.85-3251
ER  -