1. N. A. Lange (ed.), “Handbook of Chemistry” (McGraw-Hill, New York, 1967) p. 250.
2. “The Condensed Chemical Dictionary”, 8th Edn (Van Nostrand Reinhold, New York, 1971) p. 160.
3. L. A. Hardie, Amer. Mineralogist
52 (1967) 171.
4. P. Gay, Mineral. Mag.
35 (1965) 354.
5. Idem. ibid.
35 (1965) 347.