1. Birch, A. J., Fortschr. Chem. Org. Naturstoffe, 14, 186 (1957); Proc. Chem. Soc., 3 (1962).
2. Thomas, R., Biochem. J., 78, 748 (1961).
3. Gatenbeck, S., Svensk Kem. Tidskr., 72, 188 (1960).
4. Stickings, C. E., and Mahmoodian, A., Chem. and Indust., 1718 (1962).
5. cf. Whalley, W. B., in Recent Developments in the Chemistry of Natural Phenolic Compounds, edit. by Ollis, W. D., 49 (Pergamon Press, 1961).