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Helldén A, Odar-Cederlöf I, Larsson K, Fehrman-Ekholm I, Lindén T.Helldén A, et al. Among authors: larsson k.BMJ. 2007 Dec 22;335(7633):1305. doi: 10.1136/bmj.39408.393137.BE.BMJ. 2007.PMID: 18156240Free PMC article.