1. Department of Pediatrics, University of Iowa, Iowa City
2. Social, Statistical and Environmental Sciences Unit, RTI International, Research Triangle Park, North Carolina
3. Department of Pediatrics, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, Georgia
4. Division of Neonatal and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine and Lucile Packard Children's Hospital, Palo Alto, California
5. Department of Pediatrics, Wayne State University, Detroit, Michigan
6. Department of Pediatrics, Women & Infants’ Hospital, Brown University, Providence, Rhode Island
7. Department of Pediatrics, University of Texas Medical School, Houston
8. Division of Neonatology, University of Alabama, Birmingham
9. Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 10now Department of Pediatrics, College of Medicine, The Ohio State University, Columbus
10. Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
11. Social, Statistical and Environmental Sciences Unit, RTI International, Rockville, Maryland
12. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland