1. Department of Pediatrics, University of Michigan Medical School, Ann Arbor
2. Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women’s Hospital, Boston, Massachusetts
3. Susan B. Meister Child Health Evaluation and Research Center, University of Michigan, Ann Arbor
4. Department of Medicine, St Michaels Hospital, Toronto, Ontario, Canada
5. Department of Pediatrics, Alpert Medical School of Brown University, Providence, Rhode Island