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van Keulen HM, Otten W, Ruiter RA, Fekkes M, van Steenbergen J, Dusseldorp E, Paulussen TW.van Keulen HM, et al.BMC Public Health. 2013 Feb 6;13:111. doi: 10.1186/1471-2458-13-111.BMC Public Health. 2013.PMID: 23388344Free PMC article.
ten Hoor GA, Ruiter RA, van Bergen JE, Hoebe CJ, Houben K, Kok G.ten Hoor GA, et al.BMC Public Health. 2013 Nov 23;13:1091. doi: 10.1186/1471-2458-13-1091.BMC Public Health. 2013.PMID: 24266906Free PMC article.