1. F. E. Nicodemus, Directional Reflectance and Emissivity of an Opaque Surface, Vol. 4, 7, p. 818 (July 1965).
2. L. A. Jones, The Gloss Characteristics of Photographic Papers, J. Opt. Soc. Am.6, 140 (1922).
3. H. J. McNicholas, Equipment for Measuring the Reflective and Transmissive Properties of Diffusing Media, J. Research NBS 13, 211 (1934) RP704.
4. H. J. McNicholas, Absolute Methods in Reflectometry, BS J. Research 1, 29 (1928) RP3.
5. M. H. Sweet, An Improved Photomultiplier Tube Color Densitometer, Jour. SMPTE 54, 35 (Jan. 1950).