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Gregory PJ, Ingram JS, Brklacich M.Gregory PJ, et al.Philos Trans R Soc Lond B Biol Sci. 2005 Nov 29;360(1463):2139-48. doi: 10.1098/rstb.2005.1745.Philos Trans R Soc Lond B Biol Sci. 2005.PMID: 16433099Free PMC article.Review.