1. Saxton, J. E. in The Alkaloids: Chemistry and Physiology, Vol. 20 (Eds.: R. H. F. Manske, R. G. A. Rodrigo), Academic Press, New York, 1981, pp. 10-25
2. Nakagawa, M. in The Alkaloids: Chemistry and Pharmacology Vol. 34 (Ed.: A. Brossi), Academic Press, New York, 1989, pp 1-75
3. Nielsen, P. H. in Alkaloids: Chemical and Biological Perspectives Vol 13 (Ed.: S. W. Pelletier), Permagnon, New York, 1999, pp. 163-236.
4. Cordell, G. A.; Saxton, J. E. in The Alkaloids: Chemistry and Physiology, Vol. 20 (Eds.: R. H. F. Manske, R. G. A. Rodrigo), Academic Press, New York, 1981, pp. 10-25;
5. (b) Hino, T.; Nakagawa, M. in The Alkaloids: Chemistry and Pharmacology Vol. 34 (Ed.: A. Brossi), Academic Press, New York, 1989, pp 1-75;