Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 10,2019, Pages 660-665, doi:10.3760/cma.j.issn.0529-567x.2019.10.003
Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 10,2019, Pages 710-713, doi:10.3760/cma.j.issn.0529-567x.2019.10.012
Chinese Journal of Obstetrics and Gynecology, Volume 54, Issue 10,2019, Pages 691-695, doi:10.3760/cma.j.issn.0529-567x.2019.10.008