I. J. Pemberton, G. R. Smith, T. D. Forbes, and C. M. Hensarling (1993). "Technical note: an improved method for extraction and quantification of toxic phenethylamines from Acacia berlandieri." J. Anim. Sci.71 467-70. http://www.journalofanimalscience.org/content/71/2/467.full.pdf