TY  - RPRT
TI  - Uncertainty in determining thermal performance of liquid-heating flat-plate solar collectors 
AU  - Streed, Elmer
PY  - 1981
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS TN 1140
DO  - 10.6028/NBS.TN.1140
ER  -