1. Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts (M.P.C.)
2. University of British Columbia, St. Paul's Hospital, and the Centre for Health Evaluation and Outcome Sciences, Vancouver, British Columbia, Canada (R.S.)
3. Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada (K.P.)
4. Surrey Memorial Hospital, University of British Columbia, Surrey, British Columbia, Canada (S.N.S.)
5. University of Arizona College of Medicine, Phoenix, Arizona (M.A.)
6. University of British Columbia and Lion's Gate Hospital, Vancouver, British Columbia, Canada (A.C.D.)
7. University of British Columbia, Vancouver, British Columbia, Canada (M.G., R.J., K.H., C.S.)
8. McGill University Health Centre, McGill University, Montreal, Quebec, Canada (A.L., K.D., C.C., J.T., G.C., C.P.Y.)
9. Banner University Medical Center, Phoenix, Arizona (Z.S.)
10. London Health Sciences Centre, London, Ontario, Canada (A.M.)
11. University of British Columbia and Vancouver General Hospital, Vancouver, British Columbia, Canada (D.S.)