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Stephan BC, Brayne C, Savva GM, Matthews FE; Medical Research Council Cognitive Function and Ageing Study.Stephan BC, et al. Among authors: matthews fe.Age Ageing. 2011 Jul;40(4):501-7. doi: 10.1093/ageing/afr057.Age Ageing. 2011.PMID: 21673136Free PMC article.