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Raine-Fenning N, Campbell B, Collier J, Brincat M, Johnson I.Raine-Fenning N, et al.Ultrasound Obstet Gynecol. 2002 Jan;19(1):69-75. doi: 10.1046/j.0960-7692.2001.00608.x.Ultrasound Obstet Gynecol. 2002.PMID: 11851972Free article.