1. See e.g. L.J. de Jongh in “Magneto Structural Correlations in Exchange Coupled Systems, ed. R.D. Willett, D. Gatteschi and O. Kahn, Reidel, 1983.
2. P. Chini, Gazetta Chimica Italiana 109:225–240 (1979).
3. “Transition metal clusters”, ed. B.F.G. Johnson, Wiley, 1980.
4. G. Schmid in “Structure and Bonding”, 62:51–85 (1985).
5. M.N. Vargaftik, V.P. Zagorodnikov, I.P. Stolyarov, I.I. Moiseev, V.A. Likholobov, D.I. Kochubey, A.L. Chuvilin, V.I. Zaikovsky, K.I. Zamaraev, and G.I. Timofeeva, J. Chem. Soc, Chem. Commun., 937 (1985).