1. Standard specification for nighttime photometric performance of retroreflective pedestrian markings for visibility enhancement (ASTM Publication No. E 1501-1999);American Society for Testing and Materials [ASTM],1999
2. Luminance-brightness comparisons of separated circular stimuli;Booker;Journal of the Optical Society of America,1981
3. Light as a true visual quantity: Principles of measurement (CIE Publication No. 41);Commission International de l'Eclairage,1978
4. International lighting vocabulary (CIE Publication No. 17.4);Commission Internationale de l'Eclairage,1988
5. On luminance additivity and related topics;Guth;Vision Research,1969