1. bDean, F. M. In Advances in Heterocyclic Chemistry; Katritzky, A. R., Ed. Academic Press: New York, 1982; Vol. 30, p 167.
2. cDean, F. M.; Sargent, M. V. In Comprehensive Heterocyclic Chemistry; Bird, C. W., Cheeseman, G. W. H., Eds. Pergamon: New York, 1984; Vol. 4, p 531.
3. Natural sesquiterpenoids