Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 11,2019, Pages 736-740, doi:10.3760/cma.j.issn.0529-567x.2019.11.004
Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 11,2019, Pages 762,
Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 11,2019, Pages 741-746, doi:10.3760/cma.j.issn.0529-567x.2019.11.005
Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 11,2019, Pages 747-750, doi:10.3760/cma.j.issn.0529-567x.2019.11.006