1. University of Washington School of Medicine; Department of Medical Education & Biomedical Informatics; E-312 Health Sciences Box 357240 Seattle WA USA 98195-7240
2. University of Pennsylvania School of Medicine; Department of Pediatrics; The Children's Hospital of Philadelphia 34th and Civic Center Blvd Philadelphia PA USA 19104
3. University of Michigan; 3110 Taubman Centre Ann Arbor MI 48109-0368 USA
4. University of Michigan; School of Public Health; 109 South Observatory Street Ann Arbor MI 48109-2029 USA
5. St George's, University of London; Community Health Sciences; Cranmer Terrace London UK SW17 0RE