1. CIE Technical Report, TC-2.3, Retroreflection, Publication CIE No. 54, Bureau Central de la CIE, Paris, 1982.
2. Standard Practice for Describing Retroreflection, ASTM Designation: E 808-81, American Society for Testing and Materials, Philadelphia, 1981.
3. Standard Practice for Measuring Photometric Characteristics of Retroreflectors, ASTM Designation: E 809-81, American Society for Testing and Materials, Philadelphia, 1981.
4. Standard Test Method for Coefficient of Retroreflection of Retroreflective Sheeting, ASTM Designation: E 810-81, American Society for Testing and Materials, Philadelphia, 1981.
5. Federal Test Method Standard 370, Instrumental Photometric Measurements of Retroreflective Materials and Devices, General Services Administration, Washington, DC, 1977.