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Smith JE, Rockett M, Squire R, Hayward CJ, Creanor S, Ewings P, Barton A, Pritchard C, Benger JR.Smith JE, et al. Among authors: pritchard c.BMJ Open. 2013 Feb 14;3(2):e002577. doi: 10.1136/bmjopen-2013-002577. Print 2013.BMJ Open. 2013.PMID: 23418302Free PMC article.