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Nelen WL, Blom HJ, Steegers EA, den Heijer M, Thomas CM, Eskes TK.Nelen WL, et al.Obstet Gynecol. 2000 Apr;95(4):519-24. doi: 10.1016/s0029-7844(99)00610-9.Obstet Gynecol. 2000.PMID: 10725483