1. Department of Pediatrics, Duke Clinical Research Institute, Duke University, Durham, North Carolina
2. Department of Pediatrics, Emory University, Atlanta, Georgia
3. Case Western Reserve University, Rainbow Babies and Children's Hospital, Cleveland, Ohio
4. Research Triangle Institute, Research Triangle Park, North Carolina
5. Brown University, Rhode Island Hospital, Providence, Rhode Island
6. National Institute of Child Health and Human Development, Bethesda, Maryland
7. University of Miami, Jackson Memorial Hospital, Miami, Florida