1. Schaeffer Center for Health Policy and Economics, Sol Price School of Public Policy, University of Southern California, Los Angeles
2. Los Angeles County Department of Public Health, Los Angeles, California
3. Keck School of Medicine, University of Southern California, Los Angeles
4. Sports Medicine Research and Testing Laboratory, Salt Lake City, Utah
5. LRW Group, Los Angeles, California
6. Stanford University School of Medicine, Palo Alto, California