1. Vanderbilt University Medical Center, Nashville, Tennessee, USA
2. Harvard School of Public Health, Boston, Massachusetts, USA
3. Johns Hopkins University, Baltimore, Maryland, USA
4. University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
5. University of California, Los Angeles, Los Angeles, California, USA
6. University of Southern California Keck School of Medicine, Los Angeles, California, USA
7. Case Western Reserve University, Cleveland, Ohio, USA