1. Extremely short cervix in the second trimester : bed rest or modified Shirodkar cerclage;Skupski;J Perinat Med,2014
2. cerclage is not a modified total cervical occlusion;Dräger;J Perinat Med
3. cerclage is not a modified total cervical occlusion;Dräger;J Perinat Med
4. Extremely short cervix in the second trimester : bed rest or modified Shirodkar cerclage;Skupski;J Perinat Med,2014