1. University of Michigan School of Medicine, Ann Arbor, Michigan
2. Veterans Administration, Veterans Affairs Medical Center, Ann Arbor, Michigan
3. Dow Division of Health Services Research, Department of Urology, University of Michigan, Ann Arbor, Michigan
4. Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee
5. Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
6. Department of Urology, NorthShore University Health System, Evanston, Illinois