1. C. Edeleanu, Nature173, 739 (1954).
2. Theo Heumann, Passivierende Filme and Deckschichten (Springer-Verlag, Berlin, 1956), p. 256.
3. Ya. M. Kolotyrkin and G. M. Florianovich, Khim. Nauk i Prom.3, 483 (1958).
4. N. D. Tomashov, M. M. Kurtepov, and E. N. Mirolyubov, Zhur. Fiz. Khim.32, 904 (1958): Abstracts of Proceedings of The All-Union Scientific and Technical Conference on Corrosion and Protection of Metals [in Russian) (Profizdat, Moscow, 1958),Col. 1, p. 17.
5. N. D. Tomashov, Uspekhi Khim.24, 453 (1955).