1. A. Dohme, E. Cox and E. Miller, J. Am. Chem. Soc., Vol. 48, p 1688 (1926).
2. E. Bousquet, US Patent, 2,146,007 (1939).
3. J. Brown, D. Johnson, A. Robertson and W. Whalley, J. Chem. Soc., p 2019 (1951).
4. D. Cram, J. Am. Chem. Soc., Vol. 70, p 4240 (1948).
5. Dictionary of organic compounds, 4th edn, Eyre & Spottiswoode Publishers, London, Vol. 2, p 1112 (1965).