1. Centers for Disease Control and Prevention National Center on Birth Defects and Developmental Disabilities Atlanta Georgia USA
2. Birth Defects Registry New York State Department of Health Albany New York USA
3. Seattle Children's Hospital Seattle Washington USA
4. University of Washington School of Medicine Seattle Washington USA
5. Spina Bifida Association of America Arlington Virginia USA
6. Division of Population Health Surveillance South Carolina Department of Health and Environmental Control Columbia South Carolina USA
7. University of South Florida Tampa Florida USA