Williams, E. H.; Bunkley-Williams, L. Three Anomalies: A Scythebill in the Greater Antillean Grackle (blackbird), a Crown Pattern in the Rock Beauty (angelfish), and a Double Spot in the Butter Hamlet (grouper), and Their Possible Genetic Significance. Rev. Biol. Trop. 2006, 54, 161–169.