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Chakravarty KK, Gray RE, Webley M, Byron MA, Wozniak J.Chakravarty KK, et al. Among authors: byron ma.Postgrad Med J. 1991 Apr;67(786):358-61. doi: 10.1136/pgmj.67.786.358.Postgrad Med J. 1991.PMID: 2068029Free PMC article.