1. Wood, C. A. “A Colour Reproduction Index”, 3rd Year Project Report, Polytechnic of Central London (1985).
2. Pointer, M. R. “Measuring Colour Reproduction”, Royal Photographic Society, Proceedings of the symposium on Colour Imaging Systems, Cambridge 1986.
3. Reid, D. G. “Verification of a Colour Reproduction Index”, 3rd Year Project, Polytechnic of Central London (1990).
4. International Standard ISO 5/3-1984 (E), “Photography—Density measurements—Part 3: Spectral conditions—.