1. Tschesche, R.; Kaubmann, E. U. InThe AlkaloidsChemistry and Physiology; Manske, R. H. F., Ed.; Academic Press: New York, 1975; Vol. XV, p 165.
2. Schmidt, U.; Lieberknecht, A.; Haslinger, E. InThe AlkaloidsChemistry andPharmacology; Brossi, A., Ed.; Academic Press: New York, 1985; Vol. 26, p 299.
3. Joullie, M. M.; Nutt, R. F. InAlkaloids: Chemical and Biological Perspectives; Pelletier, S. W., Ed.; John Wiley & Sons: New York, 1985; Vol. 3, p 113.
4. Gournelis, D. C.; Laskaris, G. G.; Verpoorte, R. InProgress in the Chemistry ofOrganic Natural Products; Herz, H. F. W., Kirby, G. W., Moore, R. E., Tamm, C., Eds.; Springer: New York, 1998; Vol. 75, p 1.