1. L. B. Pfeil, U.K. Patent no. 459848 (1937); U.K. Patent No. 574088 (1945).
2. D. P. Whittle and J. Stringer,Phil. Trans. R. Soc. London A 295, 309 (1980).
3. J. Stringer,Mater. Sci. Eng. A 120, 129 (1989).
4. E. Lang (ed.),The Role of Active Elements in the Oxidation, Behavior of High Temperature Metals and Alloys (Elsevier Applied Science, London, 1989).
5. Materials Science Forum,1989