1. Omaha VA Medical Center and University of Nebraska Medical Center; Omaha
2. University of Nebraska Medical Center; Lincoln
3. University of Nebraska Medical Center; Omaha
4. University of Alabama at; Birmingham
5. George Wahlen VA Medical Center; Salt Lake City Utah
6. Washington DC VA Medical Center; Washington
7. Dallas VA Medical Center; Dallas Texas
8. Omaha VA Medical Center; Omaha Nebraska
9. Palo Alto VA Medical Center and Stanford University; Palo Alto California
10. University of Florida; Gainesville
11. Université Laval; Québec, Québec Canada