1. Y.Y. Lim and R.S. Drago, Inorg. Chem., 11 (1972) 1334; R.M. Richman, T.C. Kuechler, S.P. Tanner and R.S. Drago, J. Am. Chem. Soc., 99 (1977) 1055; R.S. Drago, T.C. Kuechler and M. Kroeger, Inorg. Chem., 18 (1979) 2337; M.H. Dickman and R.J. Doedens, Inorg. Chem., 20 (1981) 2067; P.F. Richardson and R.W. Kreilick, J. Am. Chem. Soc., 99 (1977) 8183; O.P. Anderson and T.C. Kuechler, Inorg. Chem., 19 (1980) 1417.
2. C. Benelli, D. Gatteschi and C. Zanchini, Inorg. Chem., 23 (1984) 798.
3. W. Beck, Inorg. Chim. Acta, 99 (1985) L33.
4. D. Jahr, K.H. Rebhan, K.E. Scharzhans and J. Wiedemann, Z. Naturforsch., Teil B, (1973) 55.
5. S.C. Tenhaeff, K. Covert, M.P. Castellani, J. Grunkemeier, C. Kunz, T.J.R. Weakley, T. Koenig and D.R. Tyler, Organometallics, 12 (1993) 5000.