1. Manual on Significance of Tests for Petroleum Products, Duroff V. G. Ed. (ASTM, Philadelphia, 1989), 5th ed., Chap. 4, p. 31.
2. Gary J. H. and Handwerk G. E, Petroleum Refining Technology and Economics (Marcel Dekker, New York, 1984), 2nd ed., p. 8.
3. Annual Book of ASTM Standards, Petroleum Products, Lubricants and Fossil Fuels (ASTM, Philadelphia, 1990), Vol. 05.04, pp. 13, 21, 26.
4. Materials Characterization Using Factor Analysis of FT-IR Spectra. Part 2: Mathematical and Statistical Considerations