1. Center for Reproductive Medicine Henan Key Laboratory of Reproduction and Genetics First Affiliated Hospital of Zhengzhou University Zhengzhou China
2. Department of Obstetrics and Gynecology Stanford University School of Medicine Stanford CA USA
3. Department of Obstetrics and Gynecology Hacettepe University School of Medicine Ankara Turkey
4. Center for Reproductive Medicine Cheeloo College of MedicineShandong University Jinan China