1. F. Dolder, Ch. Tamm and T. Reichstein, Helv. Chim. Acta, 38, 1364 (1955).
2. N.G. Bisset, Ann. Bogor, 2, 219 (1957); Chem. Abstr., 52, 12090d (1958).
3. N.G. Bisset, Planta Med., 10, 143 (1962).
4. K.K. Chen and F.G. Henderson, J. Pharmacol. Expt. Therap., 150, 53 (1965).