1. Hillis, W. E., Nature, 175, 597 (1955). “Symp. Vegetable Tannins”, Soc. Leather Trades Chem., 121 (1956); Aust. J. Biol. Sci., 9, 263 (1956).
2. King, H. G. C., and White, T., J. Soc. Leather Trades Chem., 41, 368 (1957).
3. Roux, D. G., Nature, 181, 1454 (1958).
4. Freudenberg, K., and Weinges, K., Ann., 613, 61 (1958).
5. Hancock, W. V., Forest Prod. J., 7, 335 (1957).