1. Drickamer H G 1965Solid state physics, Advances in research and applications (eds) F Seitz and D Turnbull (New York, London: Academic Press) vol. 17, p. 1 and references therein
2. Ferguson L N 1973The modern structural theory of organic chemistry (New Delhi: Prentice Hall of India) p. 200
3. Foster R 1969Organic charge transfer complexes, (London, New York: Academic Press) and references therein
4. Ikemoto I, Chikaishi K, Yakushi K and Kuroda H 1972Acta Cryst. B28 3502
5. Kommandeur J R and Hall F R 1961J. Chem. Phys. 34 129