1. Amerace Corporation, Retroreflective sheeting, US Patent 4,672,089 (1987).
2. Minnesota Mining and Manufacturing Company, Wide-angle-reflective cube-corner retroreflective sheeting, US Patent 4,703,999 (1986).
3. US Department of Transportation Federal Highway Administration, Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects, 1996, pp. 750–762.
4. S.A. Heenan, et al., Retroreflective articles having microcubes, and tools and methods for forming microcubes, US Patent 6,015,214 (2000).
5. F.A. Jenkins, H.E. White, Fundamentals of Optics, 4th ed., McGraw-Hill, New York, 1976.