A study on classification method of sky luminance distribution part I. Classification of sky luminance distribution by coefficient of correlation between measured sky and cie standard sky.
Standardization of Luminance Distribution on Clear Skies. 1973
Natural daylight. Official recommendation. Compte Rendu CIE 13^<th> Session 1955. 1955, II, II-IV & 35-37
Spatial distribution of Daylight-Overcast sky and clear sky. 1994
MOON, P. Illumination from a non-uniform sky. Illum. Engng. (N. Y. ). 1942, 37, 707-726
KITTLER, R. Standardization of outdoor conditions for the calculation of daylight factor with clear skies. Proc. the CIE International Conference on Sunlight in Buildings. 1967, 273-285