1. Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia
2. RTI International, Research Triangle Park, North Carolina
3. Department of Pediatrics, University of Iowa, Iowa City
4. Department of Pediatrics, University of Alabama at Birmingham
5. Department of Pediatrics, University of Texas Health Science Center at Houston
6. Department of Pediatrics, Warren Alpert Medical School of Brown University and Women & Infants Hospital of Rhode Island, Providence
7. Department of Pediatrics, Wayne State University, Detroit, Michigan
8. Department of Pediatrics, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, Ohio
9. RTI International, Rockville, Maryland
10. Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland