1. San Antonio Military Medical Center, San Antonio, TX
2. Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA
3. Children’s Hospital of Philadelphia, Philadelphia, PA
4. University of Pittsburgh, Pittsburgh, PA
5. Connecticut Children's Medical Center, Hartford, CT
6. Children’s Hospital of Wisconsin, Milwaukee, WI
7. University of Pennsylvania Center for Clinical Epidemiology and Biostatistics, Philadelphia, PA
8. University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA
9. Washington University in St. Louis School of Medicine, St. Louis, MO