1. ASTM Standards on Color and Appearance Measurement, 4th ed., ASTM, Philadelphia (1994).
2. International Organization for Standardization, “Paints and Varnishes—Determinations of specular gloss of non-metallic paint films at 20°, 60° and 85°,” ISO 2813 (1994).
3. R. S. Hunter,The Measurement of Appearance, Wiley, New York (1975).