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van Empel IW, Nelen WL, Tepe ET, van Laarhoven EA, Verhaak CM, Kremer JA.van Empel IW, et al. Among authors: nelen wl.Hum Reprod. 2010 Jan;25(1):142-9. doi: 10.1093/humrep/dep362. Epub 2009 Oct 27.Hum Reprod. 2010.PMID: 19861329