1. H. Sings, S. Singh, Alkaloids: Chem Biol 60, 51 (2003)
2. T. Miedaner, Geiger. H. H. Toxins 7, 659 (2015). (and references therein)
3. P.S. Steyn, R. Vleggar, Progress in the Chemistry of Organic Natural Products (Springer, New York, 1985)
4. P.G. Mantle, P.B. Mortimer, E.P. White, Res. Vet. Sci. 24, 49 (1977)
5. M.E. DiMenna, P.B. Mantle, Ibid 24, 347 (1977)