1. Mingos, D. M. P., Nature Physical Science, 236, 99 (1972).
2. Wade, K., Electron Deficient Compounds, 150, 185 (Nelson, London, 1971).
3. Snaith, R., and Wade, K., Internat. Rev. Sci. Inorg. Chem., Ser. 1, 1, chapter 4, 141 (MTP-Butterworths, London, 1972).
4. Wade, K., Chem. Commun., 792 (1971).
5. Wade, K., Abstracts, Chem. Soc. Autumn Meeting, B22 (1971).