1. Faculty of Medicine, University of Bern, Bern, Switzerland
2. Department of Gynecology, University Hospital and University Zurich, Zurich, Switzerland
3. Department of Obstetrics and Gynecology, Cantonal Hospital of Fribourg, Fribourg, Switzerland
4. Medical Library, University Library of Bern, University of Bern, Bern, Switzerland
5. Department of Obstetrics and Gynecology, Inselspital, University of Bern, Bern, Switzerland