1. 10) M. MORITA : Proc. The Third Asian Coating Forum (1990), p. 49
2. 11) R. S. HUNTER : The measurement of appearance (1975), p. 68 [John Wiley & Sons Inc., NewYork]
3. 12) J. S. CHRISTIE, Jr. : J. C. T., 51 (1979) 653, p. 64
4. 16) F. GOODIER : J. O. C. C. A., 47 (1964), p. 867
5. 17) DIN 50960