Garraffo, H. M.; Spande, T. F.; Jain, P.; Kaneko, T.; Jones, T. H.; Blum, M. S.; Musthak Ali, T. M.; Snelling, R. R.; Isbell, L. A.; Robertson, H. G.; Daly, J. W. 2001. Ammonia chemical ionization tandem mass spectrometry in structural determination of alkaloids. II. Tetraponerines from pseudomyrmecine ants. Rapid Communications in Mass Spectrometry 15:1409-1415. PDF