On the Evolutionary Origin of Cyclooxygenase (COX) Isozymes: CHARACTERIZATION OF MARINE INVERTEBRATE COX GENES POINTS TO INDEPENDENT DUPLICATION EVENTS IN VERTEBRATE AND INVERTEBRATE LINEAGES -- Järving et al. 279 (14): 13624 -- Journal of Biological C...

http://www.jbc.org/cgi/content/abstract/279/14/13624