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Baer AN, Witter FR, Petri M.Baer AN, et al.Obstet Gynecol Surv. 2011 Oct;66(10):639-53. doi: 10.1097/OGX.0b013e318239e1ee.Obstet Gynecol Surv. 2011.PMID: 22112525Review.
Johnson MJ, Petri M, Witter FR, Repke JT.Johnson MJ, et al. Among authors: witter fr.Obstet Gynecol. 1995 Sep;86(3):396-9. doi: 10.1016/0029-7844(95)00186-U.Obstet Gynecol. 1995.PMID: 7651650