1. (a) K. Wade, in B. F. G. Jonhson (ed.), Transition Metal Clusters (Wiley and Sons, Chichester, 1980), pp. 193–264.
2. (b) D. M. P. Mingos, D. J. Wales, Introduction to Cluster Chemistry (Prentice-Hall, Englewood Cliffs, 1990)
3. T. A. Albright, J. K. Burdett and M. H. Whangbo (1985). Orbital Interactions in Chemistry, John Wiley & Sons, New York
4. (a) H. G. Ang, C. M. Hay, B. F. G. Johnson, J. Lewis, P. R. Raithby and A. J. Whitton (1987). J. Organomet. Chem. 330, C5.
5. (b) C. M. Hay, B. F. G. Johnson, J. Lewis, P. R. Raithby and A. J. Whitton (1988). J. Chem. Soc. Dalton Trans. 2091