1. A.G.C. Gwyer,Z. Anorg. Allg. Chem., 49, p 311–319 (1906).
2. C.R.A. Wright,J. Soc. Chem. Ind., 11, p 492–494 (1892):13, p 1014–1017 (1894).
3. W. Campbell and J.A. Mathews,J. Am. Chem. Soc., 24, p 255–256 (1902).
4. L. Guillet,Bull. Soc. Encour. Ind. Natl., 101 (2), p 259 (1902);Rev. Met. (Paris), 18 p 461 (1921).
5. H. Pécheux,C.R. Acad. Sci. Paris, 138, p 1501–1502 (1904); see also143, p 397–398 (1906).