1. Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, Texas
2. University of Medical Sciences, Poznan, Poland, and Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
3. Jackson Memorial Hospital, University of Miami, Miami, Florida
4. National Institute of Perinatology, Mexico City, Mexico
5. Hospital São Paulo, University of Sao Paulo, Paulista School of Medicine, Sao Paulo, Brazil
6. Regional Clinical Hospital Guillermo Grant-Benavente, University of Concepción, Concepción, Chile
7. Neonatology Clinic, Warsaw Medical University, Warsaw, Poland
8. St Charles Medical Center, Bend, Oregon
9. Discovery Laboratories, Doylestown, Pennsylvania
10. Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts
11. Statistics and Consulting Unit, Department of Mathematics and Statistics, Boston University, Boston, Massachusetts