Smith DM, Grasty RC, Theodosiou NA, Tabin CJ, Nascone-Yoder NM.  2000. Evolutionary relationships between the amphibian, avian, and mammalian stomachs.  Evol DevNov-Dec;2(6):348-59.

Thompson CM, Capdevila JH, and Strobel HW. 2000. Recombinant P450 2D18 Metabolism of Dopamine and Arachidonic Acid. Journal of Pharmacology and Experimental Therapeutics. 294(3), 1120–1130.