1. Obst Gyn, Practice of prenatal medicine Erfurt, Germany
2. Ultrasound, Prenatal Medicine München, Germany
3. Prenatal Medicine, Klinikum Leverkusen gGmbH, Leverkusen, Germany
4. Obstetrics and Prenatal Medicine, University-Hospital, Bonn, Germany
5. Center for ultrasound and prenatal medicine, Frankfurt am Main, Frankfurt, Germany
6. Gynecology and Obstetrics, Practice of prenatal medicine Weimar, Germany