1. Based in part on R. C. Livingston, Honors Thesis, Williams College, Williamstown, MA (1992).
2. and Heterocyclic Compounds, Vol. 7, p. 237. Wiley, New York (1961).
3. The Carbolines
4. The Alkaloids, Chemistry and Pharmacology, Vol. 8, pp. 47 and 55. Academic Press, New York (1965).
5. and The Alkaloids, Chemistry and Pharmacology, Vol. 22, p. 1. Academic Press, New York (1983).