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2. Hatfield, W. E., Whyman, R.: Trans. Met. Chem. 5, 47 (1969)
3. Massey, A.: Comprehensive Inorganic Chemistry, (Ex. Ed. Trotman-Dickenson, A. F.), Oxford, Pergamon Press, Vol. II (1973) p. 1
4. Hathaway, B. J., Billing, D. E.: Coord. Chem. Rev. 5, 143 (1970)
5. Hathaway, B. J., Tomlinson, A. A. G.: ibid. 5, 1 (1970)