1. J. M. Demarthe, L. Gandon, and A. Georgeaux:Int. Symp. on Copper Extraction and Refining AIME, 1976, Las Vegas. Edited by J. C. Yannopoulos and J. C. Agarwal, Chap. 43, pp. 825–48.
2. C. Hoepfner: U. S. Patent 507, 130, Oct. 24, 1893.
3. C. Hoepfner and H. Orth: U. S. Patent 704,639, July 15, 1902.
4. M. Bonan:Thése Ing. doct., 1977, Univ. des Sci. et Tech, de Lille (France).
5. U. R. Evans:The Corrosion and Oxidation of Metals: Scientific Principles and Practical Applications, Chapter XX, Edward Arnold, London. 1960.