1. Centers for Disease Control and Prevention; Division of Reproductive Health; 4770 Buford Highway, Mail Stop K-34 Atlanta Georgia USA 30341-3724
2. University of North Carolina, School of Medicine; Obstetrics and Gynecology; CB#7570 Chapel Hill North Carolina USA 27599-7570
3. FHI 360; Clinical Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA 27709
4. FHI 360 and UNC School of Medicine; Quantitative Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA NC 27709
5. Prevessin-Moens France