1. T. R. Bates: unpublished research, Shell Development Company, 1978.
2. R. B. Heady:Corrosion, 1977, vol. 33, p. 98.
3. O. A. Onyewuenyi: unpublished research, Shell Development Company, 1982.
4. R. E. Reed-Hill: “Physical Metallurgy Principles”, D. Van Nostrand Co., Inc., Princeton, 1964, pp. 252–72.
5. G. Herbsleb and R. K. Poepperling:Corrosion, 1980, vol. 36, p. 611.