Chinese Journal of Obstetrics and Gynecology, Volume 46, Issue 9,2011, Pages 684-689, doi:10.3760/cma.j.issn.0529-567x.2011.09.010
Chinese Journal of Obstetrics and Gynecology, Volume 46, Issue 9,2011, Pages 709-711, doi:10.3760/cma.j.issn.0529-567x.2011.09.017
Chinese Journal of Obstetrics and Gynecology, Volume 46, Issue 9,2011, Pages 701-704, doi:10.3760/cma.j.issn.0529-567x.2011.09.015
Chinese Journal of Obstetrics and Gynecology, Volume 46, Issue 9,2011, Pages 655-657, doi:10.3760/cma.J.Issn.0529-567x.2011.09.004