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Harstad I, Jacobsen GW, Heldal E, Winje BA, Vahedi S, Helvik AS, Steinshamn SL, Garåsen H.Harstad I, et al. Among authors: helvik as.BMC Public Health. 2010 Nov 4;10:670. doi: 10.1186/1471-2458-10-670.BMC Public Health. 2010.PMID: 21050453Free PMC article.