1. Leiden University Medical Center; Department of Gynaecology, Division of Reproductive Medicine; PO Box 9600 Albinusdreef 2 Leiden Netherlands NL 2300 RC
2. FHI 360; Clinical Sciences; PO Box 13950 Research Triangle Park North Carolina USA NC 27709
3. FHI 360 and UNC School of Medicine; Quantitative Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA NC 27709
4. Leiden University Medical Center; Department of Gynaecology, Division of Reproductive Medicine and Dept. of Clinical Epidemiology; PO Box 9600 Albinusdreef 2 Leiden Netherlands NL 2300 RC