1. Beecher CWW (1986) The biosynthesis of protoberberine and related alkaloids. Ph.D. thesis, University of Connecticut, pp 92–96
2. Beecher CWW, Cordell GA (1990) Biosynthesis of Drugs. In: Swarbrick J, Boylan JC (eds) Encyclopedia of pharmaceutical technology. Marcek Dekker, New York, pp 89–116
3. Beecher CWW, Mahady GB, Schilling AB (1990) The analysis of some isoquinoline alkaloids from cell cultures by particle beam LC/MS. In 38th ASMS Mass Spectrometry and Allied Topics, Tuscon, USA, pp 1087–1088
4. Berlin J, Forche E, Wray V, Hammer J, Hosel W (1983) Formation of benzophenanthridine alkaloids by suspension cultures of Eschscholtzia californica. Z Naturforsch 38c:346–352
5. Caolo MA, Stermitz FR (1979) Benzophenanthridinium salt equilibria. Heterocycles 12:11–14