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Barratt A, Irwig L, Glasziou P, Cumming RG, Raffle A, Hicks N, Gray JA, Guyatt GH.Barratt A, et al. Among authors: irwig l.JAMA. 1999 Jun 2;281(21):2029-34. doi: 10.1001/jama.281.21.2029.JAMA. 1999.PMID: 10359392No abstract available.
Bell KJ, Kirby A, Hayen A, Irwig L, Glasziou P.Bell KJ, et al. Among authors: irwig l.BMJ. 2011 Jan 21;342:d12. doi: 10.1136/bmj.d12.BMJ. 2011.PMID: 21257657Clinical Trial.