1. and Tetrahedron Letters 4635 (1969).
2. and Structure Elucidation of Natural Products by Mass Spectrometry, Vol. 1, Holden-Day, San Francisco, 1964, Chapter 5.
3. in (Ed), Fortschritte der Chemie organische Naturstoffe, Vol. 24, Springer-Verlag, New York, 1966, Chapter 1.
4. Identification of two new β-carboline alkaloids in South American hallucinogenic plants