1. Thompson, P., J. Am. Oil Chem. Soc.24, pp. 387–8 (1947). See also Report of Oil Color Committee, J. Am. Oil Chem. Soc.25, 271–6 (1948).
2. Official and Tentative Methods of the American Oil Chemists' Society. Second edition (1946). Cc 136–45, B.
3. Hardy, A. C. Handbook of Colorimetry, pp. 9, 33. The Technology Press (1936).
4. Ibid. Hardy, A. C. Handbook of Colorimetry, pp. 9, 33. The Technology Press (1936), p. 4.
5. Levens, A. S. Nomography, pp. 68–75, Wiley and Sons (1948).