1. Center for Health Policy Research, University of California, Irvine, CA.
2. VA Long Beach Healthcare System, Long Beach, CA.
3. Division of General Internal Medicine and Health Services Research, University of California, Los Angeles, CA.
4. Department of Community Health Sciences, University of California, Los Angeles, CA.
5. UCLA Center for Health Policy and Research, Los Angeles, CA.
6. Department of Neurology, University of California, Los Angeles, CA.
7. VA Greater Los Angeles Healthcare System, Los Angeles, CA.