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Whitfield AG, Howarth FH, Farr RF, Roberts AW.Whitfield AG, et al. Among authors: howarth fh.Br Med J. 1971 May 29;2(5760):514-5. doi: 10.1136/bmj.2.5760.514.Br Med J. 1971.PMID: 4397130Free PMC article.No abstract available.